If you have to ask, "Should I shave my head?", then the answer is always, "Yes." It's that simple. It really is, because you would not be asking the question if some part of you didn't really want to do it.
If you are not experiencing any hair loss and want to shave your head, you should do it now while the look is still popular. Trends come and go, and if this one goes and you haven't tried it, you'll have missed a great opportunity. It will be much harder to shave once something else is "in style". Hair grows back pretty quickly; you can get to a 1/8" buzzcut in one week's time.
If you are experiencing hair loss, then shave your head immediately. A shaved head has become the standard haircut for balding men. A completely bald head always looks better than thinning or receding hair. If you're still in the early stages, your hair might still look good and you may want to hold onto it a bit longer. But I really recommend shaving sooner rather than later. Once you're headed down the road to baldness, it's easier to just get it over with. Save yourself the anxiety of watching your hairline shift in an unflattering pattern. Accept your fate and embrace the new you.
I know it's a hard thing to do, especially the very first time. But once you do it, you'll be so glad you did. Ask any guy who shaves his head, and I'll guarantee that he'll tell you that his only regret is that he didn't do it sooner.