Try this easy at home exercise.
Do a couple hundred sit ups everyday.
It will flatten your tummy faster than anything else I know. You probably won't do that amount in the beginning, but work up to it every day. You can do situps while watching your cooking shows on TV. If you need help, get your child or sig other to hold your feet down while you raise your body up.
You will hurt the first week or so, but keep doing it, you will be amazed at the results. And oh yeah, start walking a mile or two every day. Its the best calorie burner in the world.
What are you doing to lose weight? A healthy diet and moderate exercise are the best ways to lose weight.
Turning 50 is a milestone and a good time to get healthy.