Why don't I like talking about my feelings?

I'm a girl, and so a lot of people ask me why I don't take about feelings and stuff. Ever since I was young I was always the tom-boy so it was never an issue. But I've been in High School and a while now and my friend was like 'Why are you so closed, like you don't take abut yourself or nothing.' I mean, I do sometimes talk about myself, but nothing like really too deep. I asked my sister once what she thought and she was like 'You live with mommom (my grandmother) and you know she don't like it when we be getting all babish and stuff' and I guessed she was right 'cause she use to live with us but now she with my Mom. Anyway, I think I do wanna talk to someone, but I thik I'm scared I'll be rejected or something, or maybe I have no one to talk to. Anyway, I don't know.