You are about to have a bunch of people tell you that it isn't healthier to lose more than 2-3lbs a week... just to warn you. lol. I know because I've posted something close to this and gotten the responses. Seriously, I say just do it. Just get into an exercise program, exercise is recommended at minimum 3 times a week, and substitute non-healthy things, like mine was potatoe chips, I eat fruit everytime I crave chips. I'm taking diet pills too, which a lot of people disagree with, but I say do whatever your heart desires to lose, as long as it's nothing that will hurt your health in the long run... like binging and purging or starving yourself. Welcome!
I agree with ashisback...go for it! Do what works for you and makes you happy, as long as you aren't harming yourself. However, be a bit flexible with your numbers so you don't set yourself up for disappointment if you come within a lb or two. And anything above is just frosting on the cake!
I must agree with Jay. As long as it's a medicaly supervised program, then it must be okay. But you must do some research along the way and learn the proper way to eat and what a proper portion is and learn how many calories your body will need to maintain at the lost weight. Otherwise, you will find yourself back in the same boat you started out in.
Keep in mind that weight loss starts fast then slows down, so don't get discouraged if it starts slowing as you start weighing less. Aside from that, WELCOME! And good luck on your journey!