How many calories should I eat if Im on a diet?

Well my mom said under 1500 calories , and she said I COULD eat junk food. but not ALOT of junk food (lets get this straight , only eat freaking pop tarts and small bags of chips that I like, but I don't eat it alot) . I am 5'3 and weight 167 lbs (do NOT judge me =() and I was trying to see if I could lose 5 pounds by the end of june, if that's possible . Oh and if I excercise for 30-45 mins a day .