Suggestions to market yourself as a relatively new fitness professional over 50 include:
1. Check with your local YMCA to see about teaching one or two classes a week. Great way to meet others and develop a following.
2. If you have classes you are teaching, Craigs List is a free way to advertise in your immediate & surrounding areas.
3. Offer free intro classes to your local churches and suggest a class in the church (or at your normal location).
I hope these ideas help!