Im not a parent but do have a 11 year old sister and im 22 she was not allowed to go out intil she left junior sch this time last year and even then i made sure she new what she could and could'nt do (being street wise etc) and new how to use a phone wot we got for her.
and even then her mates had to meet her at my house so we new who she was with and not walking round trying to find them on her own. i dont live in a bad area but i grew up around here and i know wot goes on.

imho 6 is to young to go out on your own. when i have kids wot wont be to far away i dont think i would let them out at that age and i now have my own flat in the same situation as yours..