Not sure of your exact age, sounds like you are close to me, I just turned 60. I didn't learn to play the guitar I purchased at 17 until I was 56. I finally decided I was going to learn to play 1 song. That would be a major accomplishment.
Things have progressed since then, but it all starts with a goal. It can be as simple as learning a song.
This year the diet is definitely gonna stick!