This post is old I doubt the op will be back.
It's probably because of the coitus or sex. Her body is probably preparing for a possible pregnancy since it "feels" she's sexually active. When a woman starts having sex, a lot physiological changes can take place in her body, obviously, the most noticeable, pregnancy. Had she ever BEEN pregnant?
Also, you said "over the years" so I'm guessing you've been dating much before she was 22. If that is true, then you've also just seen natural development, women continue to develop until the early 20s, so that, along with sexual relations can be the 'cause of their growth.
I'm sorry, I what I meant is "How old are you", because this is a very awkward question to ask on a forum,unless you are under age.
Pregnancy or with age. How are you?..this is an awkward question to ask.
Some times people nipples can get large from weight gain , pregnancy or even sometimes it is just possible for this to happen as the person gets older !!
If this was a gradual change I would think the only reason would be a significant amount of weight gain.
If this is a sudden change then the only explanation I found online is pregnancy.
sorry for the typo, you know what I meant.
did her nipples get bigger or her areolas (the skin darker skin around the nipple)?
no she is not pregnatnt and she is 22