My 19 and a half year-old girlfriend's breasts really differ in size. The left breast is a nice plump B cup, the other is barely there.

Thanks to the internet, I know that this is completely normal and that they will even out by the age of 21/22. But is it possible that this does not happen? Not that it makes a difference to me - I love her no matter what - but I don't think she likes it.

Thank you :)