Ha, I started when I was 15 by using Microsoft Image composer and frontpage express!!! Ohh the old days.
NogDog, I'm down for storytime around the campfire!
Is it normal to be a web designer at 15?
Sure, why not. When your 15 you have alot more free time then you imagine. Even with homework and extra curricular acitivies, haning out and what not, it still leaves the typical teenager alot of free time to do what ever you can. The question I think really becomes what do you fill that time with. Web design is as good as any to delve into, but I do think like I think was hinted at that you can spend some of that free time just enjoying yourself too. I dont mean partying, but web design can be fun but I it also a career oriented task. If I could go back I'd start playing guitar sooner (started at 20), taking more photography courses, just enjoying myself with the knowledge that when you graduate college and need to start paying bills, years becomes days because you'll spend much of your time just either getting to, being at, or coming from work or work related activites.
But what ever it is you choose. The IT industry is booming right now, with alot of working coming in from overseas the market is also rapidly changing. There is no way to tell how the market will be when you are ready to come into the scene profesionally, but I can pretty much say that there will at least BE a software industry, and the more you know about it the more chances you have of succedding. Be sure it's what you want to do if you are going to spend alot of your time doing this though. You'll be suprised how quickly you change your mind about what you want to do after a certain age.