I don't know if she's good enough for you, since you have proven the quality of your character, and she hasn't had the chance yet to prove herself with the world. But you seem to have a high opinion of her, so go it. There is a lot to said about social and economic classes, and much of it is hogwash. The circumstances you are born into often define your outlook, but is not the end all and be all. Rich people can have a low quality character as easily as poor people, or middle class people. The same for a high quality character.
For some people material possessions and background are important, and if she is this way, she might like you for a while but not be satisfied with you for long. If she is more interested in how she looks to the world than in the substance of her world, then your image probably won't suit her.
On the other hand, if she is a person with a high quality character, how you act, not what you have, is more important. It shouldn't matter how much money either one of you have in your pocket, since this is not what personal relationships are based upon. It is based upon mutual interests and the spiritual and moral values you have in common.
Go for it, and if she turns you down, or dumps you after a short time, at least you tried. You will not have the regret that comes from not trying, and you will learn something.
As to the how in your question, just walk up to her and tell her that you would like to get to know her better. Suggest doing something together that is safe and non emotional, like having a soda together (or coffee or an ice cream cone, whatever) that will give you a chance to talk. Pick any activity that has people around and gives you a chance to talk. Going to a school game is good if you want to ask her on a date. Movies and dancing tend to not give you a chance to talk. They are actually designed so people don't have to talk on dates. Miniature golf is good for talking.
Don't bother trying to live up to her old boyfriend. If he was that good she would have kept him. Being an athlete doesn't make someone a good person, except to their fans, if they have any. Just be yourself, your real self. Don't spread the bull, don't lie, don't brag or boast because you feel insecure or have to live up to something. All you have to do is be you and give her a chance to learn who that is.
There are a million women looking for a guy like you, and if she doesn't see the good in you, I know that someone else will.
