How many calories should an 11 year have a day?

I just turned 11 2 days ago I started my period early january and i'm a cup size 32 A full I weigh 86 pounds and I'm 4, 11. I just started lacrosse and at recess i usually play man hunt and when i come home at 2:35 i'm outside till 5:30 dancing ballet, stretching, climbing a tree, throwing and doing drills with my dad, doing homework, and reading. I feel more hungry lately and I'm worried I will get fat instead of getting more skinny. How many calories should I have a day after I eat like a small sandwich with 1 egg and 1 piece of bacon on it for dinner i'm still hungry what does this mean?, I really don't want to get fat or chubby. How many calories should i have a day ?