i am an english rider but I did learn how to ride western when I was younger.
english is very different from western, all of the aids are different and if you are aiming to ride english properly i'd suggest that you get a good instructor - just being able to jump doesn't mean you can ride english . . . I've been riding since I was 3, i'm 18 now and i've pretty much done show jumping / hacking all my life.
at the moment I am learning how to do dressage (properly) as well as schooling my imported show-jumper in dressage and I must say i'm finding it quite difficult !