I first started my period at age 11 or 12. I was already 5'7 in height around age 14. I was wondering if my breasts are going to grow any bigger in my twenties? I am a size B right now. If my breasts hurt when I'm eating or when I'm on my period does that mean my breasts are growing? I also heard drinking whole milk will make my breasts grow; is that true? What about skim milk? How fast can my breast grow from one cup to an upper cup? How would I know when my body finishes growing? Some girl told me her breasts grew two cup sizes at age 23. Thank you.
You stop growing when you reach the fifth stage of development. You can estimate which stage you are in by using the Tanner Stage Calculator for Girls. One of the primary indicators for where a girl is at in her development is the shape (not size) of her breasts. You can find a description in the discussion on the Tanner stages.
Soreness in your breasts generally come from tissues being stretched. As your breasts develop and expand in size, they will be tender. They also become tender near the time of your period because women tend to retain fluids just before their menstrual periods. Just as your feet might temporarily swell a bit, so will your breasts and this can feel uncomfortable. Once the period is past, the swelling reduces and the tenderness goes away.
Since breasts are mostly fat tissue, if you put on weight, your breasts will become larger. This is not because they are still growing, it is only because they are holding more fat. So in an indirect way, drinking whole milk which contains 4% fat by volume can lead to weight gain and, thereby, larger breasts. Skim milk contains very little fat and is less likely to cause you to gain weight.
Some girls get used to eating all they want during their teenage years and not gain weight because their bodies are growing. If they don't control their appetites after growth stops, they will continue to get bigger -- not because of growth, but because they are gaining weight. So yes, some women in their twenties do end up with larger breasts -- and larger hips, and larger stomaches, and ... You get the picture.