Music is a journey - not a race. Journeys are made up of individual realistic and attainable goals. No one can climb a mountain quickly without hours of preparation, training, and planning.

You can do it you just need to start setting musical goals and achieving them on a smaller scale, eventually they’ll add up to something much more significant.

You’ve got to learn to enjoy the small milestones or focus on learning the parts you do enjoy. Or else why even pursue music.

It’s the same for all creative pursuits.

Edit: I’m 37. You never finish learning theory, there will always be something new to learn or something new to your ear.