Aibu to expect a few manners at 16?

[arethereanyleftatall]

I genuinely don't know if I'm bu as my dcs are younger.
We have sil and niece staying with us for two weeks. Dn is 16.
I have organised loads of stuff for her to do, I've paid for them all, no problem there. The activity yesterday was something dn really wanted to do,, and for various reasons it became clear to her that the rest of us had sacrificed something else for her to do this. No problem, our choice. But, here's my problem, at no point has she said thank you or expressed Any appreciation for anything. Now, my dcs are 9&7, so I don't think they would know or care who pays for activities out of mum or aunty, but by 16 is it unreasonable to expect a bit of gratitude?
She also has not helped in any way round the house, i don't mean I expect her to get the vacuum out, but things like not clearing her own plate. Am I expecting too much?

Surely it is up to SIL to monitor your niece's behaviour? So if you are cross at anyone it should be your SIL. And at 16 I'm pretty sure I didn't want to have stuff organised for me, but then maybe I'm just an ungrateful cow..... However I will say that although I was/am painfully shy I always had/have excellent manners!

Is she shy? My DD is 16 she would say thanks but probably not help around the house as she would be scared of doing the wrong thing. If you asked her though she would do it.

Yes, SIL helping.
They have a live in maid in their own home, so I don't think dn has ever had to do anything.

Not unless she's been taught to have manners, clear up after herself etc. If she doesn't do it at home, it probably wouldn't even occur to her to do it elsewhere

Your house, your rules. On the domestic front, you don’t need to make an earnest big deal about it. You just use your ‘mum voice’ to say

‘Ok, all finished? Right Kylie can clear and Pete and I will wash up. Tomorrow before ‘xx treat’ we’ll all need to pitch in cos it’s sheet changing day. The littlies can strip their beds, just ask Cousin Kylie for help if you need it. SIL and Kylie please strip yours and seperate all the sheets into colour piles and put the whites on. I’ll put the rest on when we get back’.

If you think Kylie should be more grateful, by all means take her aside and ask her to please thanks the others (not you) for putting her preferences first. Include your SIL in the people she should thank. It’s a bit hard for SIL to take offence at you ‘criticising her parenting’ if she’s being thanked. Or buy the ingredients and pointedly say ‘and I’m sure Kylie won’t mind making a cake for tomorrow’s dinner, to thank everyone for yesterday’ and steer her towards the kitchen.

But maybe that’s just me! I’m not one for fuming in the background!

Well then - she probably doesn't know that she ought to be helping. Ask her to do specific stuff.
Teens are a weird species - they like to think they are all grown up, but can be really quite shy when offering themselves up to do stuff (especially if she doesn't know you that well?). They will usually muck in when asked to do so though - just don't seem to have the awareness to volunteer.

Please and thank you though should always be the case.

IME, teeanagers with live in staff can end up a bit clueless about this sort of thing. You need to be a bit more direct and ask her to take her plate away. She might mistake you for staff otherwise and fall into lady of the manor mode. I don’t think it’s deliberate.

I’ve experienced a bit of this, many years ago, with some acquaintances who had had live in staff all their lives. Ended up in a bit of an upstairs downstairs scenario while visiting one of them . I was too young and not confident enough to say “fuck off I’m not sleeping in a tent in the garden because you’ve given my bed to one of your ghastly school friends”. Wouldn’t happen now!

Thanks everyone.
I'll cut her some slack and request nicely.