A Normal BMI as per latest scores is between 18 to 24 you should understand though your BMI is towards the lower range ,this is not a underweight.
Next Steps
Help me understand the reason for gaining height and weight through online consult on Practo
Health Tips
Include Variety of whole cereals, whole Pulses, green leafy vegetables sprouts , fruits Nuts and other vegetables, dairy and eggs and other lean meat portions with optimum Activity.