How can I get rid of my stretch marks?

I am 15 years old and I have stretch marks on my hips, butt, and breasts. My skin is brown. Like, Puerto Rican. My stretch marks are lighter than the rest of my skin, and very unattractive. I've tried cocoa butter, but not religiously. I've also heard that tanning helps? I just wanna get rid of them because theyre really ugly and embarrassing.