Hi Don,
I started about a year and a half ago and I'm really enjoying it, and starting to play in sessions now. You're never too old to learn, in my opinion. I don't think you need a very fancy instrument to start, but definitely don't get the base model. As others have said, it will be very hard to play and discourage you. Also check this course from one of the best players out there. It's organized extremely well and will get you up and playing very quickly. https://www.irishconcertinalessons.com/course_introduction/1
Here's my story if it helps.
First I put out a call on Facebook to any friend who might have a concertina I could try out to see if I liked the feel of it. From that I tried an English Stagi, which was pretty hard to play, but definitely got me excited about really learning.
I knew I wanted to play Irish, and found the Mcneela website with their different models. I then found a lightly used Swan for sale on the forums here for about half off retail. I think Mcneela is having a black Friday sale now also. The Swan has been great for learning, high enough quality to be playable but not break the bank if you don't end up liking it.