You might want to visit www.acefitness.org and look at Operation Fit Kids. That might give you some direction.
I assume that you will be talking to seniors. However, my comments pertain to any other audience.
As you discuss the different options, try to intersperse it with questions like: “Who ever took an aerobics class (kick-boxing, Pilates, …..)”? Ask for a show of hands. Ask who knows a personal trainer. Ask what they would look for in a personal trainer. You can ask whether they can name exercises.
With all that, you try to keep them engaged and create some relevance to their own experiences.
Be mindful of your own presentation style. If you are asking for input beyond a show of hands for a numerical count, you need to be prepared to take that input and incorporate it into you presentation on the fly.
Good luck and have fun.