Hi
First of all I like your moxy, I had a similar plan when I was your age. I will be honest it didn't go well (that was back in the mid-late 90's), but you only need a few clients and you've made quite a bit of money compared to having a 'real' job so its definately worth trying (as long as you are persistent).
For registrar use namecheap, and then for host try Fanst.net they are really cheap and uk based.
Set up a skype account and advertise your services on Gumtree, as well as doing direct sales attempts with face to face marketing.
Make sure you have at least 2 or 3 dummy sites live to show you know what you are doing when you go to meet prospective clients.
Hope that helps a bit.
Tal