I took a look at your profile and I don't agree - I think you look pretty. It doesn't even look like you have any makeup on and not even models look good without makeup. I also like your hair. When I was younger my hair was always straight and I wanted curly hair. We always want what we don't have. After I had my girls, if I don't blow dry my hair it goes curly - it so weird the way it changed - but I like it and leave it like that sometimes.
You could straighten your hair but honestly I think it's pretty. That's awesome you're athletic and good at sports - keep focusing on that. There another thread here where a poster posted pictures of stars without makeup - what a difference. Are you willing to try a little makeup or do you like the natural look? I always give this Dove website to young women who I think need a self esteem boost. Don't compare yourself to others and learn to appreciate your own uniqueness. I truly think you look good.
http://www.dove.ca/ click on 'Campaign For Real Beauty'