MOVE IT !
So you have decided to move it ! well done now take exercise one day at a time.
The key to sustaining a workout routine is to enjoy it. Don't compare yourself with others because you are unique. Instead, make a progress sheet of your exercise so you can check your performance. If you ran for thirty-minutes yesterday, why not run an extra five more today? This simple act can help you progress and reach your fitness goal. Remember, your size is not a hindrance to becoming healthy.
Running is not for all of us some people find it just too hard so try this, start with a walk then run intermittently to help speed up your metabolism. If you are on a treadmill try to include a short run every couple of minutes for as long as you can then return to a walk speed to catch your breath. If you are walking outside why not try and run between telegraph poles!
Most people push too hard because they want to speed up the results. However, the right approach is to respect your body and let it recover. Once you have recovered or rested well, then you can repeat the exercise again the following day. Make sure that get enough sleep and hydration is also very important to replenish lost fluids especially on intense sessions.
Be active and exercise no matter what size you are you will feel much better for it.