I started my martial arts training as an older adult.  I would sit and watch my youngest son train and after a while I decided to try out the class and about 21 years later I am still training and having fun. 

The many benefits I have found in training has been the self-confidence in learning new techniques, weight control (or loss) as you are exercising regularly along with better flexibility, improve your mental focus on every day activities, and for me it is a good way to help relieve stress.