Stretch marks help!

Hey everyone, I was 14 when I first noticed I had stretch marks on the sides of my bottom. They were pretty faint and there were only a few, but I’m 16 now and they’re developing quite quickly. I have a few more in a distinct line shape (like stripes) across each side of my cheeks.

I was looking into the causes of stretch marks and I have not had any significant weight gain or loss in my life, so I’m unsure why I’m developing them. Purely for self esteem and confidence reasons I was wondering if anyone has any tips on how to prevent further stretch marks or even fade them or remove them completely!