How old are you? Who clocked you at 83 and what did they use? 83 is smokin quick for a 9th grader. Good Job. Don't be terribly let down if your speed drops or fluctuates over the next 4 years. The best way to get to the 90's as a Sr. is to get yourself a game plan (Weights, diet, conditioning, mechanics assessment and work), stick with it and adjust as needed as you find out what you need or don't need. The 90's aren't easy to reach and stay at (My son who is a jr. clocks 86-90 depending on the who what and where), you have to make a big time commitment and effort, as well as staying on top of your grades and prepping for SAT's. You look like you have a good start. If you can come up with the cash, get Steven's Tuff Cuff, it will help you set up and track your journey...really a super training aid.
Good Luck to you.