Looking at yourself in the mirror, you ponder your condition, stroking your beard as a man would. You're surprisingly calm about the matter, even though it's a little weird. After all, you could always shave it. Nothing has changed about you, with the sole exception of your facial hair. You don't really want to shave daily, but for the moment, it doesn't seem like a major issue to hide.
Therefore, you decide to figure out how your powers work first. Still fiddling with your beard, you head to your computer and begin to look up shapeshifting. You figure the genie had to base the concept of shapeshifting on something, so folklore and old tales might give you some clue as to the rules of the act.
From what you see, there are a couple of main ways shapeshifting work. Either a god zaps you (which doesn't feel too far off with what happened with the genie), you utilize an object or ritual to achieve a shift (like an animal skin or a spell), or you naturally have the capability, although it might require certain conditions to be met (think full moon for a werewolf). While it sounds interesting, you're still not sure how your shapeshifting works. Assuming you have absolute control, your power does not depend on an object or ritual, and it actually might be closer to a natural capability which requires no conditions. Therefore, maybe you should think of it like a skill like riding a bike, something you are capable of but just have to learn how to get the feel of.
However, like you thought before you made the wish, you don't want to accidentally lose your identity by not knowing how to change back, so whatever changes you make have to be easily fixed or hidden. Therefore, from now on your head is out. Instead, maybe you should pick something you can hide under clothes.
Before you continue experimenting, you grab a small scissors and trim your beard, leaving yourself a little longer goatee. It's strange, but you chuckle at your appearance in the mirror, amused by the idea of suddenly having a beard. Since you're not really scared of your ability, you decide to be a bit more adventurous, although with the goal of hiding your changes.