Crushes on your best friend

M

I’ve been friends with this guy since kindergarten and have been crushing on him since forth( I’m in sixth). I don’t believe in boyfriend/ girlfriend things at this age, but I don’t want to hurt his feelings because I’m pretty sure he likes me back. My brother, friends, and even his family says he likes me and approves of us. Also, it is kinda awkward because his sister and my little brother, age 10, are in a boyfriend and girlfriend type relationship. HELP PLEASE