Confused about intake

I'm a 5'11, 20 year old female who weighs 173 lbs. My goal is about 155/160 lbs. I currently do Pilates for about 45 minutes twice a week, and lift (pretty heavy) for an hour and do an hour of low-impact cardio 6/7 times per week (I'm hoping start running in a few weeks, but I've been recovering from a nagging injury and need to wait to be cleared to do so). Otherwise, I walk to classes but am often on my computer or studying. According to CC, my sedentary burn is a little under 2000 cals/day; according to various calculators I've found, I should eat about 3100 cals/day to maintain. 

I know I am tall and pretty active, but 2500+ cals seems like way too much for weight loss. Before counting, I would estimate I ate about that much, but was gaining. Am I doing the weight-loss math wrong? 

I'm also planning to up the fitness this summer, because I am hoping to play varsity college soccer in the fall; more (heavier) lifting, more HITT type cardio, still keeping up Pilates. Should I really eat even more then?

*edited to correct BMR vs sedentary burn  

Your BMR is 1650, not 2000. Your sedentary maintenance is about 2000, maybe that is what you were thinking of? Are you saying that you burn 1100 additional calories exercising? Because that is a lot. I doubt your maintenance is 3100. It is probably somewhere around 2300, depending on how much you burn at the gym. So a reasonable amount to eat for weight loss would be about 1800.

Original Post by solid555:

Your BMR is 1650, not 2000. Your sedentary maintenance is about 2000, maybe that is what you were thinking of? Are you saying that you burn 1100 additional calories exercising? Because that is a lot. I doubt your maintenance is 3100. It is probably somewhere around 2300, depending on how much you burn at the gym. So a reasonable amount to eat for weight loss would be about 1800.

Oops, you're right, I did mean sedentary maintenance with the 2000.
I don't own a heart rate monitor, but according to calculations done through CC I burn roughly 180 calories in 45 minutes of Pilates,  180 in 20 minutes of moderate stationary bicycling, 514 in 40 minutes of moderate elliptical (I usually do almost full-resistance for 1 minute, then lower it to 50% resistance at a 7.5/mph pace for 30 seconds, then go up to about a 10-12mph pace for 30 seconds, then repeat), and 230 in an hour of lifting (I use the "light" option, but I usually am doing a circuit with moderately heavy weights for nearly the full amount of time). It comes out to roughly 1100 calories on an average Pilates day; probably 800-900ish without Pilates. 

Do you spend 2 hours and 45 minutes working out every day?  That's a lot of working out. Did you subtract the calories you would have burned not working out from that 1100? Because that would bring the number down by a few hundred calories. To be healthy you would want to eat some of that back, I'd keep your deficit under 700.

I'd say I work out that amount only twice a week, then about 2 full hours the other 5 days, with maybe a little bit of light swimming for rehabbing my injury. 
I definitely did not even consider the subtraction bit...d'oh! I'll keep counting calories and be sure to keep my intake up. Thanks so much for your help!