1400 Calories per day? My BMI is 2281…is that okay?

2281 sounds more like your TDEE than it does your BMR. I would recalculate it elsewhere to be sure.

my advice to you is set up your profile again as sedentary and then log your exercise to get a more accurate calorie count. Then eat back your calories you burn so you stay at or above 1400. This is what I do and it works, if you're ever "starving" feeling then my advice is either eat smaller lower calorie meals throughout the day, learn to "deal" with it in the short term or just eat a snack. A banana is only 105 calories and can make you feel full because of the fiber/water content.
Also cold water helps in the beginning as your stomach shrinks down I believe because most people are used to eating way too much.

Another option is to stay off by going -100 calories each day or every couple days from where you are now until you get down to 1400.

goodluck

Something is definitely wrong, if you had a BMI that high you would weigh well over a 1000 lbs. But the good news is, I am your height and very close to my goal weight of 140, and my calories are set at 1240 a day. But you're younger and you exercise a lot more than I do. I do 1 hour of Jazzercise 3 times a week and burn 365 calories for one hour. If I am hungry, I will only eat back 1/2 of calories burned because MFP and other devices have a history of overestimating calories burned, and if you eat them all back you could easily be overeating your workouts.

You could also reset your profile to lose one pound per week and that would give you an additional 500 calories a day, if you currently have it set for a 2 pound loss.

I think you should try 1400 calories a day for at least two weeks. Make sure you are getting all your nutrients, so be conscious of the quality of food instead of just the calories. Figure out what your body craves and feed it that (offsetting the things you don't crave so much). If you have proper energy, focus and are seeing some body shifting (weight, inches or just looking at yourself in the mirror) its working.

If on the other hand, you find yourself having trouble concentrating, your diet is taking over your life and you are not feeling healthy, its probably too low.

As far as being too high, I think that exercise (walking, biking, being active) is the best way to get the additional caloric burn. I wouldn't commit to gyms or anything like that until you decide that it would be a permanent part of your life. Its easy to commit to a leisurely walk - harder to doing strength training unless you just love doing the strength training (and its a fun part of your day and not a burden).

If you're hungry, try eating more protein throughout the day. Eggs and peanut butter stick with me much longer than a lot of other foods, plus they help me work out much harder/longer. Good luck.