[girlwhofeelsbad]

So I like this guy his name is justin and he just graduated from 12th grade but I am afraid to tell him because he is my older brothers best friend and he might not feel the same way so should I tell him or let him go

[I wish]

Let go. Brother's best friend is usually very risky unless you both feel the same way.

Furthermore, he's off to university and he's going to start a new life.

Since you are in high school, it's better to find someone your own age.