I think that a 16 year old girl's breast areola size should be around a size 16
breast size should be 36 and stomach size should be 24 and bump should be 36
There is no particular "regular" size. It depends on whether or not you have reached puberty, and even then, there is no specifically "correct" size. Many 11 year olds are not even in need of this type of undergarment yet.
A 12-year old girl should wear a size 12/14. If the girl is tall, she may want to go up a size so things will fit better.
There is no average since each girl/woman is different and breast size is based on DNA.
the size 14-16 or probaly smaller12-10
34B
It depends on the size of the 12-year-old girl.
It depends on what size your breast size is. Every girl is different, don't worry.
one that fits
That depends on the size of the girls breast and chest measurments.
an 11