****s sake ladies.. I'm gunna recommend UBUNTU!
Download it, burn it and install it.
It will work well and will give you a ground to work on.
I use it on my work computer (self employed) and now use debian on my laptop (its old and slow)
I could never have set up debian without the basics i learned from ubuntu.
I really recomend you get it and give it a go... you'll then learn more when you start it at school/college/whatever it is.