Older friend

a couple weeks ago i met my friend who’s 22, i’m 17, and i knew him through one of my friends also my age. We’ve gotten really close and i consider him my best friend, he’s always there for me and i’ve even developed some feelings for him, my sister and family tell me i shouldn’t be friends with someone so much older, and that i can’t talk or see him anymore, but like i said hesmy best friend and the few feelings i’ve developed for him means i miss him heaps when i can’t see him, what do i do?