Very tiny small, not easy cyst on vagina. Is it a problem?
Answers: It might be a gland or a duct specifically just normally at hand. Have you tried looking at diagrams of the area to see if anything matches up next to what you have? Here's a diagram that shows some of the ducts and glands http://vulvaverite.com/diagram1.pdf
My sister had alike problem when she was about your age. She be convinced there was something horrible wrong with her, but the doc said it was only just normal female parts..
Maybe it is merely a mole. If it has not changed in size, it probably is not an ingrown fleece or anything serious. You are 15, and now is a good time to draw from examined by a OB/GYN. It won't hurt, the doctors are kind and it's never too soon to look out for your own health. Why own you waited five years to say something? You hold nothing to be ashamed of. it could be a problem it could not.
just see if you can parley to a gyn. he/she will know what it is.