Just answer please.
There is no average because at 13 you have only just BEGUN to go through puberty and your breasts have only just began to develop.
Though some girls start developing earlier so there boobs will be bigger, most girls at your age however have relatively small boobs that aren't noticeable.
Also things like genes will determine your breast size and other things can affect them, such as your weight and health.
At thirteen I was about 30AA now im 15 and 32DD I've outgrown most of my friends now lol. I really think it depends on genetics and your eating habits. My mom is now smaller than me but my dads mother and sister are both ENORMOUS... im hoping not to get to that but you cant change your DNA. If you want to know how big (or small) you will end up, observe the females in your family on both sides if you can.
Uhm when I was 13 I was a 34 A. Now I'm 15 and a 34 B. It really all depends on your body, genetics, and hormons.
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Welocme to my Dear Friends It is to 13 Year of Old girls breast size on 12" inch ok thanks
There is not really a normal size for whatever age...its different for every girl
if this helps, my 13 year old girlfriend has 30A. very nice indeed.
hahahahahhahaha. I had 34DD at 13 lol now im 14 and 40DD(:
I'm 14... 42D. Lmao. This is one awkward question.
There is no normal size. When I was 13 I was 36C
depends on how your body works