Maybe you heard here and there that someone lose 40 pounds, other lost 80 pounds. Yes, it can be done, but if it is not done with the mind, you will get fat again.
You have to think long term, think about a healt life everyday and start from now.How to do that ? Get used with healthy food. First will be harder, because you are not used to it, but in time you will get experience in how to prepare health food, or which are the juiciest healthy foods and you will start to hate bad food.
It is all about getting used with the new food. Spend some time without expecting the results. Think that your goal is to get used with healthy food, and invest some time in finding the healthy food with the best taste. After you find few, eat them regulary and try to replace the bad food with the tasty healthy food, and use other meals to find other healthy tasty food to fullfill your menu.