to expect my dd 14 to act a little more mature and help out with newborn

Most 14 year olds wind their parents up wanting more independence, not less. If she doesn't want to stay home on her own or go to the shop on her own, which doesn't sound like it's new behaviour, I'd be looking into what kind of anxieties she has and trying to figure out how to help her rather than suddenly dumping new expectations on her. If she's already anxious and is feeling displaced by the new baby - is this one a girl? it sounds like she's used to being the only girl - things are going to get worse unless you help her. Are you managing any one on one time with her?

Wrong time to ask.

You've managed not to parent her thus far, so she's not going to take kindly to you trying now the new baby is in the house.

Not even read the comments but from the vote it looks like most are in agreement with my thoughts.

It is not your daughters responsibility at all to look after your baby.

Other chores yes, she should be doing. One of mine doesn't like going to the shop by themselves, I'd try to find out why that is, but at 14 she should help with housework.

But again, you decided to have a baby which is no one else's responsibility but yours and your DP.

Good point.

Sorry, but you've picked a terrible time to start teaching her life skills now. That should have started years ago, and now she's pissed off and spoilt. You're going to have to rethink your strategy in dealing with her, and you have got to figure out how you're now going to teach her to be even slightly self-sufficient. She may need to be tossed into the deep end, honestly. I'd start by telling her she has to do her own laundry.

What age-appropriate chores do your two sons do around the house? What is your expectation of your sons around the house and in helping you with their sibling (age appropriate)?

I think you’re best off separating new baby and expectation of help.
Can all the children earn pocket money for doing chores? Emptying dishwasher, dryer, taking bin bag to outside bin, wiping worktops, making their own beds etc.,
Teenage years are difficult. Can you spend some time alone with dd while dad looks after the other 3?

At 14 DD is going to be a hormonal mess and with so much work to do for GCSEs. Such a bad time to bring a new baby into the mix. I get that timings can’t always be controlled, but it’s a shame it wasn’t a few years ago when she might have been excited, not mortified, by a new sibling. Anything she is asked to do now, not having been expected to help around the house before, she will blame on the baby. Still, she needs to learn these things regardless, as do her brothers, so all three need to be doing age appropriate chores around the house. Can some kind of rota be drawn up, so she can see it’s fair and not just her being asked to help? And maybe point out to her that in four years she will be off to Uni and will need to know how to shop and cook and clean for herself, so these chores are things you would be asking her to do anyway? Sounds like you’d be better off asking the younger ones to do the things that involve being around you when you’re nursing if teen is grossed by it. She will grow out of that, teenagers are just, well, teenagers!

"teenagers all think that their parents should not be having sex or even dressing sexy, in a mum's case!! and dont even talk about cleavage or breast feeding!!!"

Mentioning "cleavage", "breastfeeding", "having sex" and "dressing sexy" all together like that. They're not related at all. Breastfeeding is not sexual and breasts are only sexual if you choose to make them sexual. A teenager not wanting to hear about their parents sex life is normal and appropriate. A teenager saying that their baby sibling eating is disgusting is very abnormal and inappropriate.

I think you’ve probably got two issues going on here. The first is not fostering independence sooner - and then suddenly expecting it because there’s a new baby around.

The second is the fact that you’ve got a 14yo, a 9yo, a 6yo and now a newborn. So from the age of 5, she’s pretty much continuously had a baby or a very young sibling around and had to continuously adjust to the family getting bigger and her getting less attention/time (and lack of time probably is linked to you not having done more to foster independence). That’s a lot for a young girl.

And maybe there is the third thing of her just being embarrassed at the obvious evidence that her parents have sex!

She should be doing chores, but she doesn't have to take on the responsibility of helping to raise the other children in the house. She's not the parent.

YABU because you never prepared her for this. She should've had chores from primary age(not too late now to start with ALL the kids, including the younger ones). It's unreasonable to expect the status quo to change from one day to another because you suddenly decided she's old enough and you need help. This stuff gets built on from a young age , and then yes, at 15 it is an expectation.

You say she won't go to the shop. Has she been before on her own? Does she go out on her own/with friends at all?

I was going to nightclubs at 15.
In fact, at 14 when on holiday

Although the stuff your asking of her are not unreasonable the problem is it sounds like you babied her, now as soon as the new baby is here you expect her to grow up over night and she doesn't have the ability or confidence to do this. This is stuff you should of been doing with her for years not the second you have a newborn

Zero responsibility, really? Since we evolved as humans - or perhaps how we evolved as humans - is to cooperate, for the stronger to look out for the weaker, for people within the family or tribe to pitch in according to their capacity. What a bleak view of life, completely contary to nature, to the creation of bonds or for younger people, a sense of contribution and value within the family to assign them 'zero responsibility'.

Interesting how you continue to ignore posters who have rightly called you out for never expecting her to do chores then suddenly expecting her to help because you have a baby.

She isn't. How are you getting that from that?

@InWalksBarberalla oh nice

I don't think you can expect your elder DC to do things for baby. She didn't choose to have a baby, you did so you need to fetch this GS for baby and go to shop. She's probably feeling a bit resentful having to share her Mum after all these years of not having too. Try to find time to do something with your elder DC.

No, but I'm guessing many 14 year olds would be mortified to see their mother breastfeeding. Not that OP shouldn't of course, and hopefully the DD will come round, but I don't think it's unusual that she's a bit uncomfortable with it.

I think at her age she should already be helping around the house a bit and running the occasional errand like getting shopping. If you haven't required that of her before then that's the problem. Ignore comments about things being disgusting, that's just for attention. I don't think you should expect her to get heavily involved in baby care.

The poor DD has not been taught basic independence skills and now, at a time when she probably needs more intensive parenting than at any other time, her parents have a newborn. Cut her a bit of slack.

Well that's pretty poor parenting.

My stepson moved in with us full time at 14 when my baby was a few mounts old. I never expected or asked him to do anything. I do think he would have gone to the shops if I was desperate, but I wouldn't have needed to ask as I can't think of being desperate! There's always Ubereats or Whoosh for grocery deliveries within 30 minutes.
From your description of her behaviour it sounds like this baby was not a welcome addition for her.
He moved in because his relationship with his mother completely broke down. It's a very tricky age.