I think for a healthy 20yrs gals boobs size is about to 32B.
I think that a 16 year old girl's breast areola size should be around a size 16
I am a 11 year old girl and I have no boobs. So really the average size is none. I only have breast buds.
That depends on the size of the girls breast and chest measurments.
There is no age-chart for breast size.
There isn't actually a 'normal breast size' because everyone is different.
32A or 34A would be average bra size for a 12 year old girl.
34B
b or c
There is no average since each girl/woman is different and breast size is based on DNA.
1 cm
It depends on what size your breast size is. Every girl is different, don't worry.
The "Normal" range is from almost nothing to huge.