If only you knew then what I know now.
While yes, 16 years of ballet, tap, and jazz kept you in relatively good shape, and while yes, broccoli may have been your favorite food since you were a child, this sadly does not mean you are living a healthy lifestyle.
Even if it's walking on the treadmill on an incline for 30 minutes - DO SOMETHING. ANYTHING physical. And no, going to a spin class only once a week does not count.
as your drink of choice for the night. They are pure sugar and very high in calories. By choosing a vodka + water + lime, you will be saving yourself those empty calories.
Sleep is the best time for recovery. As you are prone to catching colds, getting an adequate amount of sleep (8-9 hours per night) will help combat those germs in your body. Coming home at 3am and waking up at 8am does not count as a full night's sleep.
As appetizing as tacos seem after a night of drinking, go home, save yourself some money, and make yourself a sandwich or a homemade burrito (so you can control the ingredients).
If you follow those simple tips, you will avoid losing the extra 15-20 pounds you will gain throughout your college years making it MUCH easier to maintain in your early to mid-twenties.
Lay the groundwork for your future body and health and you will be much happier and feel much better.