Don't let your age stop you. I have a friend older than you and she longarm quilts for hire! She's quite good.
Have you tried out different machines? You should do that before buying, to see what style suits you best. I did and found I really didn't like moving the big machine around on the carriage, over the quilt in the frame. I did love the sit down longarm, moving the fabric rather than the machine. It was much more intuitive for me. So I bought a sit down longarm (Juki 2200QVPs) and love it. It doesn't take up nearly as much space, either. They cost about half of what a frame set up costs... so that's another plus!