let me start off by saying i can sympathize.
the only thing is, i had to wear uniforms during school.
i had the HARDEST time finding a size 0 long to fit my skinny, long legs.
as far as little booty -- i can relate there too.
i STILL wear a size 5 (or XS) at the age of 20.
unfortunately i could not tell you where to try shopping,
but if i can recall correctly, Old Navy used to have my sizes back when i was a little thang.