Worryingly fragile skin. To worry about?

I have always had really fragile skin, and lately it's been getting much worse. I can scratch an itch for 10 seconds and look down to see that I've scratched off a few square inches of skin (and my nails are not sharp at all). Even if I wear boots that are the slightly wrong size I'll end up with deep cuts around my ankles instead of blisters (or nothing) like most people would get. I get bad scars from very minor injuries as well. I have scars on my feet from minor cuts I got 7 years ago. I have a scar on my torso from an injury 3 years ago that barely even broke the skin, and didn't even bleed. I have multi-inch patches of scabs on my arms and legs where I absentmindedly scratched an itch for 20 seconds and scratched off all the skin. Everything i can find online is saying that when you get old your skin gets more fragile, but I'm only 18. I don't spend a lot of time in the sun, either. Is this something to worry about?