First off, I'm not a medical person at all. However, I do remember from something I learned in school that it's can be normal for a girl while going through puberty and everything to lactate. In fact, there's been evidence that some males also have this happen. Also, contrary to common belief, it is possible for women to lactate without ever being pregnant through what's called induced lactation. This is done a lot of times with women who adopt and infant and wish to breastfeed the child. The production of milk by a woman is due to certain responses in her body, generally (but not always) brought on by pregnancy. Sometimes some women's bodies have similar responses brought on by growing up. Also, on some instances, women can naturally just produce milk. In fact, I know of a woman who has never had a child and can naturally lactate. Again, I am no medical expert, but I do not think you have anything to worry about.