You have some excellent answers. I'd add that you should know how to barbecue, if your family has one. Have whoever normally does it show you how to light the charcoal (or gas), and give you some times for various fish, meats and vegetables.
Char-broiled hamburgers, for instance, are terrific and really simple; press the patties, add salt, pepper and BBQ sauce to taste, lay on the grill, cook for 1.5 - 3 minutes a side as you like them, and serve. If you want to get REALLY fancy, use the oven broiler to toast the buns.
Going up the scale, BBQ salmon filet and grilled asparagus is what my wife asks for every year for her birthday. As a plus, if you grill there is no broiler pan/skillet/roasting pan to wash afterwards; just a few swipes with the grill brush before and after.
Not 17, but at 18 I had a job with the US Forest Service. When it was my turn, and with some friendly advice from the others, I was cooking complete dinners for our 6-man crew. I learned a lot, but at 18 (the whole crew was college students) a guy will eat anything that isn't moving too fast, so it didn't have to be perfect. Towards the end of the summer one of the guys asked me for my spaghetti recipe, so he could take it home to his mom.