question about weight

What's the average weight for a 18 year old female height of 5'7....  I don't know how much I weigh now last time i check I ranged from 175-183 I feel heavy but my jeans vary from size 7-11 (actually just recently found out I fit into a 7-8 I didn't think I did) am I overweight these past two years I've been struggling with my weight and only recently started hittin the gym...how much weight should I lose?