While your neighbor who is always posting her latest marathon results might be your motivation to start running, don't compare yourself to her. If you are a new runner and you're overweight, you are going to run slow. Accept that you are at a pace that you can handle and that you will make progress over time. Time yourself if you feel the need to compete, but only compete with yourself by comparing times from different runs.
Motivation to be a runner has to come from within. You can't decide to run because you want to be better for your kids, or for your spouse. You have to be motivated to make these changes in your life for yourself. You matter, and when you allow your health to be your motivation, you will be able to stick to a running plan easier.
Running requires shoes that fit you well and offer you the right amount of support. When you are overweight, shoes that are both comfortable and supportive are essential. If you experience pain in your feet, calves or shins after running a short distance, the pain may be caused by a lack of support in your shoes.
Cement is a hard surface without any give, while a track designed for running is going to be a better surface to run on. New runners have to be careful to start slowly, and avoiding injury whenever possible. Running on a hard surface such as cement right away makes you more susceptible to injuries, especially in your shins. Start by running on a surface that is meant for runners, even if you are shy about running in a public setting.
Don't drink a bunch of water right before you run. This will lead to cramps. Spread out your water consumption throughout the day, in order to give your body the right hydration to run effectively. You should always drink enough water, but you really need to focus on your water consumption when you want to become a runner. Training requires you to take good care of your body, and that includes staying hydrated.
As you get ready to start running, just remember that everyone starts somewhere. Go easy, and take it one day at a time. You probably won't run a mile your first day out, but eventually, you will be able to. Take your time and set your own pace.