Help

Hi would like some help to determined how many calories I should be consuming each day. When I joined fitness pal the first time 1200 seem to work for me. But this time i seem to be struggling a little. Would be great to hear what you guys think, ok here goes my current weight is 168.4, I'm 5 ft 3. My goal weight is 145 to 150. At the moment I'm doing the 30 day squarts challenge, and also walk at least 5 times a week for about 1 to 2 hrs. I do Zumba also for about 20 minutes 2 to 3 times a week.