Never make an excuse about why you can't do something. Age can be turned into an advantage rather than an obstacle. It can be seen a "new and improved" rather than "old and rusty."
Your first step is to take yourself seriously. People treat you the way you treat yourself. If you act like a king then people will treat you like one. So...if you approach people and say "would you like to see some magic" in a soft spoken tone and the voice in your head says (they're not going to take me seriously; they don't really want to see magic) then your body is going to communicate this to them...and they will treat you the exact way you're treating yourself.
You need to put yourself in a position of power. Get a restaurant to perform at, book shows, perform for as many people as possible. When you start performing shows then when you randomly approach people you will say to yourself (I do shows all over and these people are seeing this for free, they're lucky).
Instead of saying "would you like to see magic" or "would you like to see something cool"...say "would you like to see a miracle?" The response you get will be VERY different. They will say things like "Oh a miracle huh. I would love to see a miracle" or "A miracle huh...can you turn water into wine?" Instead of them wondering whether or not you're good...they become amused by your charm.
Whenever I perform, I perform like a businessman. I'm constantly talking about the "shows" I do. Before I start performing I say, "I'm going to show you guys what I do at my shows and business events"...then I constantly say things like "This is soemthing I use to do at my shows" "When I did this at one of my shows a guy had..." I'm constantly talking about what I did/do at my shows.
The key to performing like a businessman is to do things that make them want to do business with you and remind them of what they're not getting. I might create a video and post it on my blog which shows me in action on how I do this but if you constantly talk about your shows then the people you perform for will start to say, "what kind of shows do you do?"
Whenever you perform, treat yourself like a king and others will do the same