Another VR user here since Oculus DK1...admittedly I took a long hiatus from the scene in general as I didn't feel as though the PCVR space was providing the kind of experiences I wanted in awhile (primarily more atmospheric, better world building), basically meaning I'm far less into VR for kinetic-like experiences (ie motion control games) than I am to be immersed and to want to get lost in a world. Due to all the incessant raving over Astro Bot and my own disillusionment and frustration over a lack of like experiences on the PC side I just picked up a PSVR the other day and WOW! I was simply blown away all over again with Astro Bot, it really is something special.
I was skeptical my years of VR use would muddy the experience but nope, I was grinning ear to ear with tears of joy over the ecstatic state it was inducing, the Mario 64 feeling really is one of the best things to compare it to. So this experience prompted me to go and get about half a dozen other exclusives promptly on the psn store lol...helps that a lot of them are deeply discounted currently what with the holiday sale. I say this is a great time to jump in OP due to the bundle sales plus the software on sale.
If you ever do feel the novelty and wow effect fade (and as others have pointed out this really varies person to person) I suggest taking a break for a few days. I've found this helps reset your brain's acclimation to VR so you can get that initial feeling all over again for the next time you jump in. Again, ymmv when it comes to that effect fading, it might not at all (at which I'm green with envy).
Another tip I can suggest to get you more immersed is a basic meditative exercise that helps improve focus in general and I've found is quite effective in VR...focus on a close by object while in VR, it can be a wall or any object really, though the more it jumps out to you as something aesthetically pleasing or interesting looking the better. As you focus on that object study the details of the texture while also focusing on its proximity to you (the feel of how far away it appears), focus on its depth, its 3D-ness, and place in the world relative to your position. The longer you focus on it the more tangible it seems, as though you can reach out and touch it, also imagining touching the object helps too. I've found that this simple focus exercise can help bring higher awareness to your immersion levels in VR, and well, your general environmental focus and awareness as well. Sorry for the rambling, hope that helps should you ever run into a lull in your time with VR.