This is a skill I've developed, and it's as difficult as anything. I've been taking lessons from masters at things for the last decade and more, and the ability to become a student as an adult is very liberating, even if the freedom has difficult moments.
The professional benefits have also been huge, since being able to bring real confidence to situations where you are not an expert is a significant leadership trait. The confidence comes from knowing your own boundaries and being able to recognize expertise in others and use it instead of trying to emmulate it. You can also recognize skill much faster.
Imagine learning to read music as an adult and asking what the names of the strings are, what the dots on the page mean, why it doesn't resemble this other thing you think you know about, and why your skill in one area doesn't import into this one. The only path forward is work and practice. I'd imagine learning to speak a new language would be similar, where your skill level is beneath that of children.
The key is to do say, "I am going to suck at this until I suck less at it." and then the huge piece is forgiving yourself the natural conceits that your adult mind/ego puts in your way, after recognizing them. To become a student means to accept vulnerability, sometimes humilitation, even shame for the things you do wrong when you realize why you do them, and then deal with them in the psychological present instead of as just being a kid who grows out of it.
You can expect it to take 5-10 years to get as good or better than most of the kids who did something growing up. Having that horizon in mind is useful because it makes the present less urgent. Start it for the challenge, but finish it for the pleasure.