WOW, you're really a pretty girl. Actually, you're so lucky to have an oval face because this face shape flatters most of the frames. Given you situation, frames in black, brown and blue may be good choices for you.
As I know, an oval shaped face is the most well-balanced face shape. people with oval faces can wear any shape of sunglasses. So just go to an optician to choose one that suits you best. The color of sunglasses you want to choose just depends on your skin color. As I don't know the color of your skin, I am not sure which color will suit you fine. The best way is to try them on.
As you have oval shaped face, you can choose what you like, because it is said that oval shaped face can be fit for any shape of glasses. I think the tint lenses will cover your eye color. The light colored frames and the dark colored frames can go well with your strawberry blond hair. So you can have a wide range of choice. You are so lucky.
My sister has an oval shaped face too. I saw her wore a pair of big plastic framed sunglasses last summer. It looked so great. She had the same hair color with you at that time. By the way, she is really a beauty. And usually everything goes well with her. How I envy her looks! It's so unfair. why I look so plain?
Do you like vintage glasses frames? I think they can go well with your face shape. I have bought 2 pairs of this kind of sunglasses. I like them very much. But if you want to be cool with sunglasses, I suggest you to choose a pair of black or brown sunglasses. As to the shape of the sunglasses, er, you can have a look on the internet first. There are many kinds of shapes. I don't know which one do you like best. So you'd better choose them by yourself.