Just to add to the suggestions to start small. The first class I took,at the local high school, the teacher said to buy fabric for the size quilt we wanted. It was an Ohio Star cut out with templates. I needed a queen size so bought, and cut out, the fabric. 10 years later I finally forced myself to finish it. I got so sick of looking at it that it would be put away for extended periods. Techniques weren't very good, points lost etc. Ended up tying it just to get it done. It lives on my bed so all wasn't lost.
I'm sure your grandkids will treasure anything you make.

Pat

Thanks to all for the excellent comments! You've really reinforced what I was thinking--way too big a project. My idea was to do them as high school graduation or wedding gifts, but a wall hanging makes much more sense. I've done quite a bit of on-line & library research but may try a beginner class to be safe. I've been thinking about this for a couple of years, and amy trying to finally 'bite the bullet' and get it started.

Curlytop