Eating lower weight maintenance calories?

Calculators tell me that to maintain at the weight I am now, 153.6lbs, 16 y/o and 5'2", I need to eat 1900 calories a day. To maintain at about 104lbs, I would need to eat about 1600 a day. If I were to eat the second set of calories, would I eventually reach 104lbs? How long would it take?

http://www.kidsnutrition.org/bodycomp/bmiz2.h tml  Those numbers would only apply if you were totally 'sedentary'.  As your body is still growing & maturing you could find that natural development offsets some of the weight-loss.  It's not possible to say how long it would take, therefore, or even if 104lbs is achieveable.

A lightly active e.g. walking around a lot, riding a bicycle, going dancing, doing sports at school, girl of that age with those stats would need 2300 cals to maintain their weight.  So an intake of 1800 would allow them to lose weight safely.  A 104lbs 5'2" 16 year-old who is also lightly active needs 2200 cals a day.... not a lot of difference.  

 On the whole, it's better for someone your age to control their weight by choosing good quality, nutritious foods, trimming the amounts very slightly (rather than drastically) and to get at least half an hour of exercise every day.  It means you stand less chance of stunting your development or creating long-term weight-problems. Good luck

I've stopped growing heightwise, but I suppose all that still refers to bone, muscle, etc. development, so I see what you mean. I think I will raise my calories even further instead of dropping them then, and exercise more! Thank you :D