I'm new here, too! I also am the mother of two sons and was pretty inactive for most of my adult life. Last year when our oldest became engaged I decided that it was time to GET MOVING so that I would look better for the wedding next year.
I started walking first and also limiting fats in my diet. I then increased whole grains and fruits and veggies. I began having more energy and walking every day. After I had lost about 15 pounds I really began to feel a lot lighter and noticed much more energy. I went to the library and loaded up with various exercise DVDs. Some were NOT for me, but others were FANTASTIC. Now I had NO EXCUSE if it was raining or snowing and could evercise in my livingroom whenever I wanted. I began reading as much as I could find about what REALLY works to help a person lose weight. I discovered that it really was pretty simple: eat sensible portions of nutritious foods, and do daily exercise that you enjoy.
My pitfalls before were: 1) Eating portions that were too large, 2) Not exercising, 3) Eating too many fats and carbs, and 4) Not believing enough in myself.
Start slowly. Reward yourself with a pair of jeans in a smaller size that fit great or with a new CD or some other "prize" instead of food. As you lose some weight and add some muscle/get fit, you will gain energy. You really will!
Good luck on your weight loss journey!