I don't pick things up nearly as fast now (early 40s) as I was when I was younger (pre-tten, teen, 20s, and 30s). However, I also pick things up in a very different way that in some ways, are more effective than when I was young.
For example, it takes me longer to gain the intuition of something, but on the other hand, when I do, it plugs into a vaster web of knowledge. I am certainly more disciplined in both mind and body compared to when I was younger. I'm capable of clearer visualization and simulations now than before. I've got a lot more math under my belt.
I learned piano as a kid, picked it up pretty fast, and forgot a lot of it. I am not practiced in sight reading any more. On the other hand, when I poked around learning again, it's tapping much deeper into music theory, composition. For example, I learned Petzold's Minute in G Major (formerly attributed to Bach) as a kid and as an adult. I still can't quite get both hands working together as an adult ... but I was cracking up as I kept seeing how beautiful the chords are composed together in a way I never noticed as a kid.