oh geesh, I'm such a junky, I log in multiple times a day!!
Your goal is perfectly doable if you stick to it and you're patient (which it sounds like you are, else you would be stating you want to lose 4 lbs. a week!)
I've found that exercise is totally key, yes people say it can be done without exercise, and of course anything is possible, but if you don't want the weight you lose to be muscle too you'll have to work out. So make a commitment to yourself now to do all of those classes (or whatever else you want), no making excuses!
Also make a plan and commitment to your food. I also eat "mini meals" every 3 hours or so throughout the day, it works great for me. But you also need a plan for
what you're going to eat and
how much. The simplest thing to do on your own is calorie counting, IMHO, but there are so many other plans out there you can follow, it's probably just going to be a little trial and error to find out what works best for you.