I wouldn't force her to play with someone she apparently doesn't like playing with. Let her play with the older children she likes (although I guess I could see possible potential problems in the future as a preteen if she continues to hang out with kids older than her, but not necessarily). When I was a kid I didn't always like the kids my age, I preferred the company of adults. When I was in first grade I thought most of the children in my class and my age on the playground were immature - I thought it was stupid the way they made fun of some kids and I thought their games were stupid. I was into reading and studying science even from that age. Some people develop at different levels. If I were you, I'd let her be herself. I don't think forcing her to play with the girls you want her to play with will do her any good, unless maybe it would get her accustomed to playing with kids her age so when she goes to school she will be used to it, otherwise she'd have a class full of kids she has no interest in??? I don't know if that would be a problem or not. Anyway that's what I would do, but I am different than some parents in that I don't want to mold my daughter into something I want her to be; instead I will allow her the freedom to grow into her own person. But if you are really worried about it, maybe you should have a chat with some teachers or elementary school counselor, etc. to see if they have seen problems in class with children who don't like playing with kids their age. But personally I think it would be fine.