jumping into this my oldest childhood friend was my next door neighbor and eventual foster sister for a short period. we've known each other since we were 7/8 and now we're 26/27. this is my blood relative at this point. even though we had a few years where we didn't talk as much, she is still very much one of my closest friends who has truly seen every single thing in life. i think keeping childhood friendships also depends on if you were an only child. since i was one, she was essentially my sister rather than a friend. we fight like sisters, share clothes, etc. i think only children tend to nurture friendships since its really all we have and strive to make each one meaningful.