There is little or no evidence that exercising any specific part of the body causes fat to be burned from a specific area. So, if you want to lose weight from around the belly, you don't need to concentrate so hard on the abs!
Do be careful of what you eat. I think some of the debate going on has been between people who in principle agree, but are considering the consequences from different angles. It is important that you know what all this talk of calories is about so that you can make informed decisions about what you put in your mouth, unfortunately for some people this can lead to an unhealthy behavior pattern whereby the numbers start to rule their lives. This is a possible cause for eating disorders.
I am not sure if you are male or female - I would suggest that, due to your age, one contributory factor could be that your body is going through a lot of changes. Different parts of your body are developing at different rates. As my dear mother would put it - you haven't 'filled out' yet. This is important - at 17 you can't expect a full adult physique (I guess that you are male here as I've not heard any mention of 'boobs' etc!). Your shoulders aren't as broad as they will be, nor your chest, and you may find that this process will naturally over time bring what you perceive to be a 'belly' back into proportion. It just may be a little bit of excess skin that your body is making for your frame to grow into - that wouldn't be unheard of.
Finally - to get abs to show you need to have very very little body fat at all, and to achieve this goal probably would require you to look a lot harder at the nutrition requirements of the body, to eat just the right amount of the right kind of food, to count the calories in and out, to limit your sodium intake, to ensure the right amount of protein is going in, to monitor the vitamins and minerals...to avoid refined carbohydrates...the list could go on. Not to mention a structured, very disciplined exercise plan working all the muscle groups and various cardiovascular exercises.
I would suggest that this may be something for you to consider when your body has finished growing, whilst encouraging you to start doing a bit of reading into the basics.
Good luck, I hope that is helpful!