It takes about 3-5 years for breasts (including nipples) to finish developing so depending on how old you were when they began to grow, it’s possible that your breasts (and nipples) are still changing. It’s important to keep in mind that just like breasts, nipples come in many different shapes, sizes and colors, and this is all normal.
Some girls and women have nipples that appear flat but become larger or firmer when aroused, and others have what is called “inverted” nipples, where one or both nipples point inward (into the breast tissue instead of outward). Sometimes the difference is only on one side and other times the nipples appear flat or inverted on both sides.
Both girls and guys can have flat or inverted nipples that appear to be underdeveloped, when in fact they are perfectly normal. If you look at pictures of women in magazines or in movies, you may think that every woman should have breast and nipples that are a certain shape and size however, this is not the case at all. That’s why bras come in dozens of shapes and sizes!
We also recommend that you talk to your health care provider(s) about any concern(s).