How to move on from an old crush?

I've liked this boy his name starts with (c) for five years. He always talks to me and teases me. But when we got in the eighth grade we had no classes together and it made me feel so unconfortae 2 talk 2 him. My friends use to complain to me why is he ao nice to u than us and he stands ul for me.But i'm positive he only sees me as a friend and it seems him and his old crush he talked abour in the 5th grade. She lives in my neighbor hood and I get jealous when I see her, she's popular, and prettier than mr. so i'm sure he still likes her. Once I askef him in math why his nails were highlightef yellow? He said: oh morgan did it. He looked so happy when he said her name, but I think I should stop liking him so I won't get hurt.