To expect DD to be considerate towards her sibling?

[HelenLaBloodyAnnoyed]

DD is 11 and DS is 14 months (there are two more siblings in between.) DS has been walking since he was 9 months old, so it's not new news. However, I constantly have to deal with situations that arise because of DDs thoughtlessness. She will leave Lego/sharpies/coins/batteries on the floor that I then have to prise off DS, usually resulting in tears. Despite repeated reminders she keeps leaving the stair gate open, meaning I always have to be on extra high alert and repeatedly remove him from the stairs - again causing tears. She has also left it open at the top and I only just managed to catch him before he fell.

She will chase him on paths despite me asking her to do it only on grass because he's likely to trip. She will be walking holding hands with him then decide to let go and cross the road, with no thought that he'll try and follow her. Pretty much every time she has a shower, she'll leave the bathroom before drying, getting all of the kitchen tiles soaking wet which then causes DS to slip and hurt himself. She just doesn't seem to give a shit that she causes him to get upset/hurt repeatedly and seems to think I should carry him 24/7 so she can continue to do whatever she likes.

She actually adores him and is always chatting to and playing with him but just can't seem to be considerate. AIBU to expect her to be?

Well good luck, your approach obviously isn’t working, so just carry on nagging and getting annoyed.
It’s still your responsibility.

I get that you're annoyed that you think she should be doing these things, but she's not, for whatever reason.
People have offered suggestions so you can try something different, but you do seem to just be repeating how frustrated you are.
My dd is 13 and quite away with the fairies, I'm sure she would drive you mad, but there's no point getting cross with her, i just have to work with what I've got. I appreciate her better qualities and encourage her to stay on task.

The stairgate isn't really an issue unless you're not supervising your DS though? My 9yo occasionally leaves the stairgate open but my 2yo is almost always by my side at home - and if he's motors because he's with DH instead.

Same with handholding near a road - why isn't your toddler holding your hand? If he wants to hold his sister's hand and she's ok with that then fine, he has two hands, but you are the one making an 11yo responsible for the safety of a small toddler, not her.

My 9yo occasionally supervises my 2yo for a few minutes whilst I nip to the toilet or get dressed, but I made it very clear early on that he wasn't to feel pressured into "looking after" him. If 2yo does something dangerous whilst I'm out of the room the 9yo is to shout for me and I'll be there in seconds (luckily never happened though). I wouldn't leave him in charge of 2yo for any longer than I would leave the 2yo in a room by himself though.

Well op it’s not working. So if I’m right or wrong your actions currently are not improving the sisituation.

But there's a difference between not being used as a babysitter (doesn't sound like she is at all) and making things harder and more dangerous for everyone through selfishness.

She has to shut a stair gate and not leave wet floors behind her, she's 11 this is easily doable.

omg! I joined Mumsnet for advice not criticism, I have an 11 yr old daughter and feel completely the same about her atm, she has 2 older brothers And 1 younger he is 4, I find her selfish inconsiderate and challenging as all 11 yr olds are ( especially since starting secondary school !! Different Girl) but they also know all their responsibilities all of your expectations and know how to push ur buttons. This woman is having a rant like I do and wants advice not questions and criticism.