Hi there! I understand your concern. Yes working out in the gym is a great idea to build up your physique. It will help you gain muscle and may increase your height too as growth in height ceases by 18 yrs of age in males so you do have some time.
Next Steps
Have a healthy balanced diet to ensure optimal growth. Include protein rich foods like milk and it's products, pulses and dals, soya, nuts, eggs, chicken and fish if you are a non vegetarian.