STRETCH MARKS?

So recently, I noticed that on my boobs, a few stretch marks started to appear. It wasn't anything to worry about I know, and recently more appeared all around the entirety of each of my boobs, so from nipple to where they end around the edges. I turned fifteen recently but my boobs havent changed in size dramatically since about 6 months ago, when they turned into DDs. How

many of you have experienced this? Is it normal? Will they ever go away? Comments would be much appreciated :)