Make your mind that why you want to do exercise, whether your body needs exercise or the exercise needs your body? 

For good health light exercise should be done. Body building temporarily increases body mass and the body would get the same shape once a person stops to do it. 

Do walk, light jogging and it is enough for  good health.

Your weakness will be covered and for that body building is not necessary. Well if you want to do it then go to the gym and start first little bit. If you tolerate well then increase the exercises with the increase in stamina. Don't do more hard exercise and come out of the gym after doing for 30 minutes. Keep in contact with us if you face any problem during exercises. 

Next important thing is the appropriate and high calorie diet. Take honey, banana, apple, milk, butter whatever you like.