1500 is the minimum if you are sedentary, 1800 is if you are active.
Why is your Mom telling you to lose weight!? That's crazy! 5 lbs won't make ANY difference on you since you're fairly tall. It will only make you happier because it will be a lower number. Do some weights and stay active~try for 20+ minutes a day and build up and you will look better and slimmer. You do not need to lose weight!