makes us so sad/angry

my bf and i are pretty young, i’m 14 he’s 13. i get it. but we’ve been best friends for 4 years and we started dating almost 5 months ago. whenever we talk about our future together, there’s like 83 people that jump out of nowhere saying how we’re just a middle school thing and we won’t last. my best friend tells us “f*ck what they think, y’all are gonna last” but we still get so hurt that people think this about us. especially since my sister married her middle school sweetheart. people think i’m just trying to follow in her footsteps, but i don’t give a left nut how my sister lives her life, i just love my boyfriend and he loves me, and i hate that people think just because we’re young we aren’t real. it sucks. and it’s really getting on my nerves and idk what to do.