I am 23 right now - too old to start learning an instrument again.
I'm 23 right now, too. I've taught myself guitar and bass guitar (no, I'm not the greatest, but I can make music). Right now, I'm taking fiddle lessons to play local folk music. By Christmas, I want to start learning to play the accordion.
I'm trying to learn the local French dialect, as a way of preserving my heritage. I also wouldn't mind trying to learn some other foreign languages like Spanish or Japanese if I had the time.
In my opinion***, the same skills that it takes for you to understand that x++; means "add 1 to the current value of x and save it as x" and that Bonjour means "Good Day" will allow you to say that a filled in cirlce with a line coming out of it on a bar line means that you need to hold these keys down on the instrument and blow this much air for this length of time.
As someone above said, it takes practice. Whether learning the hot new scripting language, that weird foreign language that will help you in your job, or a musical instrument that makes you look like a nerd, it all takes practice.
*** I have no way of proving it, but I've heard someone really smart say something about it before, so I'm going to take the idea and run with it.