I've taught guitar on and off over the years, including to retirees- I would say you are never to old too learn. Please forgive how reductive this comment will be, it may not help at all. I do think you have to have this coincidence inside you where you can learn to love practicing, and not knowing things. The trickier or more stupid something is, the more you have to love unpacking that problem, and allow yourself to dive deep into what it is made up of. That attitude was what finally got me to stick with learning programming after years as a musician. Figure out that every obstacle is a gift you can learn from. The main thing I have found that helped me in learning is that you are not teaching your hands specific positions, you are teaching your fingers specific paths between locations. Focus on the paths.

It's partly how I learned music. It was a deep curiosity about what and why. You just like to try to emulate that sound, try all variations.

The plot twist was that it turned into "how to learn". Because you can try things blind forever and never make progress. There's a million way to be wrong in music. It teaches you patience and sensitivity. All the beautiful rhythms are very small details invisible to the newcomer, you have to go slow in order not to miss them.

The "between" trick is important. I told above about inertia and thinking about moving as constantly flowing and not as spaced points.

I had piano lessons for a year at 14. Stopped (learned nothing except 2 or 3 children melodies, and few ideas that I forgot in a week). Then started again around 19, drumsticks and bass. As I said I was almost dead wrong for 6 years. With mostly regressions.

All instruments are different though. Guitars require quite a large amount of time to adapt your left hand (neck). It's easy to never make progress there. Bass guitar is a tad easier because you play melodies and not a blend of this + chords, which are demanding in dexterity and stamina.

The frustration, abort, guilt cycle is hard to avoid. Even guys who took lessons as kids have off days. They told us on boards that when they struggle to play, they just take it easy and make it a rudiment day. Stupid patterns at slow pace, just to keep warm.

Do not ocmpare yourself to kids, it's mostly masochism. It's like comparing the speed of a fresh windows 95 install vs a 2 yo one. They have natural excitement and smoother fingers, I believe their brain is just a nasty pattern cruncher and most things end up intuitive the next day. That says nothing about your own ability to learn or take pleasure. <= pleasure which should be the goal.

One question, do you use a metronome ? everytime I struggle, 2 minutes of metronome backed practice suddenly realigns my hand and my ears and everything gets smoother. Not perfect but it helps to get properly warmed up and enjoy the feeling.

I do have a metronome and I when I use it, I pretty reliably rage quit about 4 minutes later.

One thing that I think music teachers would probably frown on is that I picked up Rocksmith and made more progress with that than practicing chord changes, scales, and Hal Leonard songs. The score for being on time on the right note with the software always adding a few more notes than I can play works really well for me.

Plus I can play it with my daughter.

Dude, do whatever works. Don't dismiss advices, try them, revisit them from time to time but walk your own path, shamelessly.

For me a metronome is not a source of frustration, it probably calibrate my sense of time and is like a wingman for locking into place. Usually it makes warm up efficient, and when my hands are loose I can just walk the neck as I feel.

I've heard the RockSmith critics. I can understand but I felt it's not a bad step, although it's quite incomparable from making your instrument sing. Kinda like driving a car vs Gran Turismo.

Fellow guitar-quitter here. I get the impression that most people that keep practicing do so because they're in a band. The stuff you practice doing has to actually feel useful to you, I think.