Well, the good thing is there's not nearly as much to wrap your head around as if you're familiar with DL but going to WDW for the first time! The entire two-park / Downtown Disney / Disneyland Hotel complex is all walking distance. Once you're at the hotel, whether you drive yourself or get dropped off, that's it; you no longer need to get in the car unless you intend to leave Disney property. No need for figuring out transportation between hotels and parks, either, so no buses or boats or monorails (unless you want to ride the DL monorail, which you should obviously do at least once). And if you have park hoppers, you literally walk out of one park and directly into the other park; it doesn't really cost you any extra time to jump from one to the other.
There are also only two parks, one of which is similar to Magic Kingdom, so you're already sort of ahead of the learning curve with that one. Don't get me wrong, it's different enough that it doesn't feel like you're just visiting another Magic Kingdom, but you probably won't feel like it's an entirely unknown situation. And since there are only two parks, your dates seem to indicate you'll have plenty of time to figure it out as you go without feeling too rushed even if you don't get your head fully around it before you arrive.
In the end, just remember to have fun and soak in all that is different! I've been going to WDW my entire life but DL only for the past five years or so, and I absolutely love both of them. In fact, I'm going to DL in a couple weeks and then WDW in April, and I'm equally excited for both trips because each experience is pretty unique.
PS - just mentally prepare yourself for the disappointment that is a WDW veteran seeing the tiny DL castle for the first time haha. Even after several DL trips, I still chuckle to myself whenever I see Sleeping Beauty Castle, having grown up with Cinderella Castle. But don't miss the great walk-through attraction you can do there!
