5`1 feet, 48 kg and 15 years, need advice. =D

Hi, I started a diet a few months ago when I  reached 56-57 kg, not exactly overweight, but not great either. Sadly, I'm an anxious person, and when I reached my goal of 48, I kept on eating 1200 cals, finally reaching 45 kilos.
My mom, worried, put me on a eating diet, I'm eating like 2000 cals a day until I reach 48 kilos. What I would like to know is how much I need to eat to maintain once I reach 48 kilos, can anybody help?

My stats:

Height; 5'1 feet or 156 cm
Weight; 48 kilos or 105.6 pounds
Age; 15
Activity; I go to the gym and jog 30 minutes plus muscle toning for 30 minutes three days a week and sometimes I go jogging with my dad on weekends.

Your best bet would be to put those stats into the same chart we use here for calculating weight loss except choose the "maintainance" instead of "weight loss" option.  Either that, or use the Calorie Expenditure - eat as much as you use and you stay stable (in theory).

What tool is that?

Oh, and is the exercise I do sedentary, or light?

The calculator is ok, but you need to fine tune it, so just start dropping 100 calores, like eat 1,900 a day for a few weeks and see if your weight stays stable, goes up or down. Does anyone really eat exactly what they are supposed to? I always go for a range...

Since your 15 your body might still be growing, so it's not like you are set at a certain amount of calories per day for the rest of your life. I'm sure you know that ;)