Squats:

The squat is the “king of all exercises”. This would help to reduce ur lower body, act on thighs and so on. You need to have firm feet to balance your body. Most people hesitate to work on squats but it is totally wrong.

The exercises are:

Sit-ups (most important, try 500 )

Half squats

Bench Curls.

Inverted bench curls.

Laid back press

Normal seat press..

It is true that the growth of height would be stopped if u start doing this so it is better to start going to the gym once your growth is over and if you are sure that you would not grow hence further.