Find someone who can give you 4-6 lessons using borrowed equipment. That will give you a good idea if you will like it and also get you started off right. I traveled the opposite direction, and learning different styles of riding is almost always to the good. But there are differences, and a good start beats trying to undo bad habits...speaking from experience, I fear!
I would also suggest taking a few lessons with an experienced trainer. Riding english is a lot more then just changing tack. I find that my students who started off western want to ride with a longer stirrup and more forward leg and have to learn to ride with more contact on their horse's mouth. Leg position is everything though, which is where good 'eyes on the ground' come in very handy!