Mixed results on calorie needs

I keep getting different results for the number of calories I need. I am a female age 15 5'2" and 100lbs sedentary lifestyle. I want to maintain this weight. I have gone to several different sites and gotten estimates as low as 1200 calories and as high as 2100 calories. I'd like to have SOME sort of calorie guideline to ensure I'm eating healthily, but I can't get consistant answers.

this is really a situation of trial and error. keep track of your weight. mark it on a mini calendar. if you gain, down them, if you lose, up them. everyone is different. :) just keep on stick with calculating and figuring our your magic number. if you have any Q's ask a dr for guidance. hope that helps :)