Yup, it's fat. You know how women get big
hips when we eat too much? Snakes have the same problem.
I would completely agree that you're feeding too much. Do you know for sure if your corn male or female? If it's a boy, I would say that feeding every 7-14 days would be best. Personally, I'd lean between every 12-14 days. If it's a girl, but you have NO PLANS of breeding her this upcoming season, go ahead and go with 10 days.
Do you have a scale? It would be best if you monitored your snakes weight. If you don't have a scale, your best bet it to get one, or to make sure you're CAREFULLY looking for signs of emancipation. Remember that while anyone (snake or human) is dropping weight, water is extremely important - so make sure there is always fresh water.
Best of luck, and give us an update when you see results