I'm really confused ? I'm only 14 , tall , not fat but have belly stretchmarks?

Stretchmarks are inevitable as a women. Some of us get them sooner than others. If you are tall, sometimes stretchmarks are from growing. I have found in life the best thing to do is realize that you can not change the way your body is but embrace it. We are all beautiful in our own way. I hope this helps :)

When you go through growth spurts, sometimes your skin grows before your bones, creating stretch marks.

I've had stretch marks on my knees and upper thighs since I was your age, and still have them.

Your friends probably grew in skin and bones at the same time.