Am i fat or is this a good weight (age 16 and a half)?

I am 16 years old and i work out 5 days a week im short , 5 foot 3 but i weigh 123. i have a pretty flat stomach i wear size 3 jeans and pants and usually medium shirts depending on where i shop. I eat relitively healthy but on occasion ill eat a lot or something not so good for you... but who doesnt? anyways do i sound heavy, most of my weight is it my legs and butt area what should i weigh i ama giail