Hi Amy, welcome! I love the graphic in your sig! You've come to the right place for support.
A lot of us have problems with emotional eating too.
If you are starting diet and exercise, you might want to see your doctor. Your doctor can tell you how to lose healthily and might refer you to a nutritionist, and s/he can also give you a physical and see if there are any exercises you should avoid. If you can't do that, I'd recommend the book "Fitness for Dummies," which you can probably get at your local library to learn more about exercise. As for calories, if you want to count calories the general recommendation is to eat 500 fewer calories per day than your body uses to lose 1 lb/week. You can google for resting metabolic rate calculators to get a general idea of how much that is. Also, never go under 1200 calories per day!
Anyway, I hope that gives you something to start with. Good luck!