I'm not Cathe, and I'm not a nutritionist, but I take the approach of "everything in moderation". I don't believe in cutting out a particular food. But educate yourself to know where the empty calories come from. You need to have an eating plan you can stick to for LIFE. For me, counting every gram of every component of every food that enters my mouth - I just can't be that obsessive! And if you forbid yourself to eat something tasty, you'll crave it all the more. Limit fast food (although some of the chains are adding healthier items lately). And find healthy snack options.
You are young, and recognizing that you need to change your eating habits now is admirable. Please don't think of it as a diet plan, but a life plan.
Diane