I would give it a chance to be a little bigger. You could certainly "pinch" the tops of them, about an inch which would encourage new shoots to develop, but I still would wait until the plant is a little older and growing more.

Looks like the same rosemary I planted for my father, but in a container at his house. I am SO jealous of his rosemary. Doesn't get full sunlight a LOT of the day (at best 2-3 hours), and it has grown quadruple it's size since I put it in its pot about a month ago, it's about 18" tall. It started about 5". I have pinched it back and the new shoots have since started developing. Comparatively, I bought several of the same type, same size and his is by far the biggest....bigger than the new ones I kept here that have the same soil mix and get even more sunlight.

We're going to his house this Sunday for a cookout, and I'll bet the darned thing has grown another 6" since the last time I saw it.

Here's a picture:

You could take maybe a single tip or two, down to about an inch or two. Its still small and doing that willl encourage more branching. Last year, I grew from seed indoors in April, and when it was planted outside it took off like a rocket. I had 15 rosemary plants all at over a foot tall by August. I even dug up a couple to give to a friend. Here, they will nbot survive a winter, so I just grow it every year. My plants were even more bushy than what is picture above. Of course I didn't plant in a pot either.

Take a little of the tips if you really must. Rosemary doesn't mind a bit of topiarising to help it even out. It'll do it anyway, given time, but I suspect you're anxious and can't wait!

The above picture I posted is of a VERY young rosemary plant. It needs to be cut back again, and will get "very" bushy and dense, even in the pot it's in. I'll pinch it back again this Sunday when I'm at my father's. Before the season is done, it will have a bigger home. :-)

It's nice having rosemary at my father's house for when I'm visiting and cooking dinner. Love it.

I plant rosemary in containers because of my zone, and I don't care for losing the plant to winter weather and just am not into the idea of starting anew every season. I DO buy a new plant just about every season, they're so hard to resist. But the ones I look fondest on are the ones I've had for a long time. I enjoy having a "history" with my rosemary...looking upon the plant and knowing I've had it for so long and it's thrived because of the care I've given it. And I've become very successful in overwintering rosemary indoors without problem. They look great inside the house in the winter, besides (not to mention I have it available to keep harvesting). And then in the spring, back outside they go. Freshly repotted, of course. :-) I seem to have no problem with the transition, and just shudder to think of planting it in-ground in my zone only to lose it during the winter. MURDER!

Mom told us to not harvest Rosemary until the second year after planting. Also not to cut back into the "woody part" or it would kill the plant.