What's a good and healthy diet for an athlete?

[banapples321]

Just last year, all I ever did was eat, eat, eat. But I wasn't overweight. I still am not. I used to eat a lot of junk, nonstop. But this year, I joined my school's soccer team, and I'm currently on the cross country team. I run every day for about 30 minutes. I love apples and bananas, but I feel like it's not good to eat too much. I want to know, what's good and what's not good to eat. Or too much of something good isn't always good? If you get what I mean. Now I don't want to go on an extreme diet, where I only eat veggies and fruits breakfast, lunch, and dinner. But can someone help me with what is a pretty good diet for a runner?
For breakfast, I have a bowl of Honey Bunches of Oats. At school, I either eat rice and meat, or a turkey sandwich. Then I usually eat meat after practice, coming home from school. For the rest of the day, I stick with fruits and veggies.
P.S. I'm 14 years old, about 106-108 lbs.
Help me please, for I feel like I don't know what I'm doing.