Question about being underweight, and maintaining?!

Question about being underweight, and maintaining?

Where my calorie needs are now, it says I need at 1500-1700 calories a day to maintain, and 1264 to lose (assuming I be sedentary)

For the past couple of months I've been plenty lower than that. Around 700-1200. If I bump up,lets say to at least 1400, will I lose/mantain/gain?

Thanks in advance (:

4'10. 85lbs 14 year old female. BMI is around 18 and my diet is very healthy plus i use a multivitamin.

at your age, you should be fine, as long as you aren't upping your carb intake...you shouldn't gain any weight. I'm glad to see a 14 year old trying to be healthily slim, just make sure to take a very high quality multivitamin(the one tablet multi-vitamins are scams and your body doesn't absorb them). If you want a recommendation, just msg me.