I am of Mom of 3 teens, including a 14 yr old. Good for you for looking at the costs, planning and budgeting from money that you have earned! I hope you have an awesome trip. I also agree with another poster, reserving at Bonnet Creek, which is right in the WDW area can save you a lot of $$$. Also, sometimes, in mid-Aug., 2 rooms at POP (at $100 per room with discounted rate) can be a lot less than 1 cabin. You won't have a kitchen, but you have a fridge, so you can still eat breakfast and make sandwiches in the room. Kids meals at POP are only about $6 and include a drink. We all get a kid's breakfast, even the adults, when we stay at WDW. Pop has a really good food court. Since you will have a car, you can easily eat offsite for a few meals. Steak and Shake is right around the corner from WDW and has many $4 meals. I have driven and gotten take out before and brought it back to the room for dinner or you can eat there--they have all sorts of food for a good price. It's right down the street from Hotel Blvd near downtown disney. There are many ways to save $$$ and still have a great trip! Have fun planning your Sweet 16!!! Maybe you can talk you MOM/Dad into going to POP for an overnight in the next year or two to check everything out for your planning? There are lots of fun things to do--pool movies, go over to Ft. Wilderness and do activities--campfire, roast hot dogs, mashmellows, movies, etc. I am from Fl and when I was a teen, we used to go to Ft W and we didn't event go into the parks sometimes. There was no POP then, or we would have stayed there.
I also let my kids pick a snack at the park each day--they look forward to it--Mickey bars, Dole Whips, etc. are all under $5, and it's a special treat.