I've always had to watch my weight, but some health issues are a great motivator to lose weight. I'm down over 40 lbs over the last 7 years, wish I could lose those last 15 lbs!
I have a friend that lost 50 lbs last year on Weight watchers. Just remember, you can't just go on a diet. You have to make changes for a lifetime that you can live with. And don't go for the quick results, you'll gain it back. Exercise is equally important, even if it just walking. Go for it!