DS was 22 months when DD was born and was much better than I ever thought he would be. Just seemed to accept her and occasionally show signs of actively liking her.
Just recently, he has been getting jealous of her and has been pushing her. She isn't mobile yet but manages to grab things that I wouldn't have thought she could (and seems to love all of DS's toy cars). A couple of days ago I was breastfeeding her and he came up, pushed at her and said "Put DD on floor, Mummy"
.
I think that as she is doing more things and I am excited about them and "praise" her, he is probably feeling left out, although I praise him a lot as well. Doesn't help that he is also in a mood of "Mummy do it" with poor DH not being allowed to do even the simplest of tasks such as lifting him down from the table.
I have been making a real effort to "ignore" DD as mch as possible today and I think he is appreciating that, but it's so hard sometimes. I keep forgetting he's only small himself, but sometimes I feel a bit frustrated.