I have decided to start an exercise routine after a long period of inactivity. I think yoga may be a good start. Any advice?

I'm 53 years old. Always had a busy life. My husband passed away in Feb. after a long battle with cancer. I guess I stayed fit just by taking care of him. Since he died I've lost 30 lbs and I am so flabby. Figure exercise may help me emotionally and physically. Advice and encouragement welcomed