How many calories should i eat if im 13 and 5'4?

It all depends on how much that 5'4" 13 year old girl exercices. Around 1800, I'd say. I'm an inch shorter and 2 years older than you, and I'm supposed to eat 2100. But of course, try to loose around 200 calories of that per day. That way, you eat a healthy amount of calories but you don't gain weight.