Yoga in the morning can do wonders for your health. After waking up, one can do Yoga. You don't need a gap between sleep and yoga. Start gently. Yoga can be done empty stomach as well.
You probably feel stiff in the morning, which is totally normal after several hours of sleeping, so it's best to focus on stretches that will gently wake up the body.
Mind, body, heart and soul – the key to becoming a healthy and happy human being lies in maintaining the wellbeing of these four components, no matter what your age.