It depends what can of physical activity you are undergoing.
Yes, your age can have an impact on how quickly your body burns off calories. But more than anything, the type of activity you undertake will be vital to working out how many calories you're using up.
If you're simply in the averages that someone in your demographic will need to take in, then a moderately active 17 year old girl should be consuming 2000 calories a day.
This is according to the United States Department of Agriculture's chart linked to here:
