TENNIS and BADMINTON
May not be such a wise move for older beginners.

If you have been a tennis, badminton or other racket sport enthusiast and have played regularly for some time, carry on, racket sports are great exercisers. However, they are explosive sports since movement and physical force can both be required in large amounts, instantaneously and frequently during a game. Also the need to continually change direction, accelerate and decelerate, usually on a hard surface, can place heavy demands on your knee and ankle joints.

This said, racket sports are an excellent way of maintaining :-

Cardiovascular fitness.

Speed and stamina.

muscle tone and power.

Bone density, particularly in your racket arm.

Balance.

Flexibility.

Research into Ageing's verdict;
First rate but if you have not played in ages, you must approach these gently and do them regularly. An occasional game may do more harm than good.