What is average bra size for 20 year old?

If you've been answered this before, you might not wanna hear this, but it's SO true when you think about it:

All girls go differently but especially boobs. There's so NO average bra size for any girl's age. It might just depend on your genes, if you're still growing or not, or more than thatpossibly. Are you petite? Because, if you are, you can grow slower.