Mapping is a different skill, but experience with playing the game definitely helps you know what the stuff you make actually feels like in gameplay. There's no real point in waiting before you start mapping if you're interested right now, though, it's not like you'll lose anything by trying it out.
Here's my advice: The most efficient way to start learning is to map stuff you can play and play the maps you make. See if the map plays how you thought it would, and if it doesn't, try to figure out how to get closer to that idea. Also, if there are any maps that you especially like playing, try to play them while paying special attention to what the map is making you do. You can also look at them in the editor to see how exactly the parts you like were made.