A.H.
I would think it would be a comination of both (age and baby on the way). My 16yr old daughter was 9 when her younger brother was born. She seemed excited at first, but once that wore off, it was more of a jealousy thing. She still doesn't really like him. But on the other hand, IMO, 12yr old girls are the most difficult to deal with....lol! I would suggest spending the day/afternoon just with her and see if that helps. And then maybe having another one once the baby is here and you're back to feeling a little better. Good luck with her and the new baby.