There are people your age that make $3000+ with their online businesses. Surely age is not an issue. You don't need to sell your own items. I suggest you start with affiliate programs. This will measure your ability to:
1. Create a website that (make it
seo friendly, user friendly, loaded with good content).
2. Promote a website (get enough targeted traffic to make your effort profitable).
If you can do those successfully than you can venture into dropshipping and maybe carrying your own products and selling online.
Before you do anything, find a niche that you enjoy and that is under serviced.