What if I'm not ready to be a mother?

I've been baby sitting these kids to see what life is going to be like with my own children. These children are very good. Very well mannered but I feel as being older I might run the fun out of my child's future like my mother did for me? She never really let me follow my dreams. When I wanted to grow up and be an actress or a singer she'd never approve of it and tell me that is never going to happen. She basically ruined my dreams. I love my mother she means well but what if I'm going to be like her? I love these kids I've been watching. Their amazing but the things they say just seem so untrue and I want to say a differ. but I just don't. I know I have to watch what I say and control myself and I will NEVER be like her. Just advice?