More calories when you exercise?

I am 16, 5 ft 3 in tall. I weigh 104 lbs. I normally eat about 1200 calories a day. I used to eat less but I know you shouldn't. I go to the gym about 5 to 6 days a week. I burn 500 - 600 calories in cardio. Because of this, I am suppose to eat more calories right? I want to maintain my same weight, so the goal is to stay fit, not lose weight. What would be a good average amount of calories to eat when I exercise? I know it all depends on the person, but, maybe a guideline? Thank you!