First of all - congratulations on deciding to change your lifestyle! It's a huge step just deciding that.
If I were in your shoes, I would start small. Find a way to move a little more every day this week, even if it's just a walk around the block. You can change the type, length and quality of your cardio as you learn more - for now, just get moving. Make some changes to your diet - I do well with introducing a few small changes at a time, rather than completely overhauling my diet overnight. Stop drinking soda, if you do. Eat one more fruit or vegetable than you normally would. Again, you can change your diet more as you go along.
I wish that when I first started dieting, someone had sat me down and told me to learn about proper nutrition
before looking into specific diets. Now that I have a better understanding of what my body needs and why, I can make more informed decisions about how I want to lose weight. If you're like me and want to read as much as possible about things, look around on 3FC. You could also check out the
Mayo Clinic's information about healthy eating.
Again - congratulations for making this decision. Start small. You CAN do this!