Losing weight is mostly diet. Exercising 5 hours a day is not the answer. Especially, if you haven't been exercising that much before. You will burn out or injure yourself. Eat healthy, reduce your calories and exercise. You should weight train to retain your muscle mass as you lose fat and cardio has a slew of medical benefits, but in terms of losing weight, is not nearly as important as your diet.
If you count your BMR, then it is totally possible to 'burn' 2500 in a day. I exercised about 1.5 hrs today and was around -3000. But do you mean can you have a net negative calories of 2500? Not safely or at least not comfortably/regularly.
You might be able to do it for a day or two now and then... I know I did in high school when I was cheerleading, 5-6 hrs of dancing at show choir practice, gymnastics and then 1-2 hr workouts when I got home. But I was also starving, angry all the time, and very sick. Had a mini-heart attack 2 years after high school graduation.
There are people on here who are able to have that as a net, but usually they are extreme athletes (or training for things like marathons) or are severly obese. It is not a great thing to have long term net losses like that. Any weight you lose, you will put it back on quickly. And if you are starving yourself, you will feel miserable. Please take care of yourself!
If you set a realistic course, toward losing 20 lb by then let's say, I think you're a lot more likely to achieve it. Better than burning out with some unsustainable plan to lose 60 lb by then, and showing up at graduation at the same or greater weight than today.
3500 calories equals a pound
Realistically, assuming that your graduation is somewhere around May 9, you have approximately 120 days to achieve a weight loss goal by graduation.
So to lose 60 pounds in 120 days, daily you would need to be at a calorie deficit of 1750. That seems rather extreme to me to maintain that sort of weight loss. Plus, I don't think it would be healthy for most people, if any.
If you shoot for losing 20 pounds in 60 days, you would need a daily calorie deficit of around 580. That should be doable. But you still want to eat enough to be healthy, even losing that weight.