Blade, your age will be an asset when it comes to meeting customers, they like us older guys because we are often more considerate and reliable.
I started out at a late age and now at 51, I am still going strong. I do yoga to work out the kinks, and keep the old body going smooth. I hope to be working in the field for another ten years, but only because I want to, rather than I need to.
I plan to work hard and play hard till the end, I can retire when I am dead.
In your case, it may be wise to get some therapy from a chiropractor, physical therapist, whatever help you can get. If your start doing labor, the problems that you have now may become more complicated, so, if your in good health, start right away and make it a slow but steady transition to the life of doing manual labor.
When you can hire some help, you will be capable of teaching and developing new human resources. Then you can retire and let them take care of business. Or you can do what I plan, and that is spend my golden years hobbling around creating new landscapes and gardens, while giving some young people a chance to learn the good old ways.