Cindy--last year I pinched some back when they were bigger. I would probably have done it sooner (mine were probably at least a foot tall at the time). They finally did branch once I pinched them, but otherwise they just grew as tall skinny plants.
I managed to save all 12 of my seedlings. Two are still very small, but considering I had to transplant them when they had barely germinated, I'm happy they lived. The others are probably 3-4" tall now.
