Deep Breathe and relax- OHHHHHHHHHHHHHHHHHHHHMMMMMMMM.

You can't hurt it, much. I bet if you ran a mower over the whole growth, it would revisit you in a few weeks and go on to produce beautiful flowers. I could be wrong, but my hope springs eternal.

The plant will find a way to get around whatever you have done to it. Pretend you're a big juicy slug, just for moment, that slithered up and chewed off the part you pinched... The plant will try its best to survive the assault, and I bet it will.
I usually wait til they're about 12-18 inches tall and pinch out the center growth because I don't have time to count leaf pairs and don't have good enough vision to see cotyledons. Cotyledons, Schmotyledons is my motto. Although I reserve the right to change my mind about them....
Just don't worry. I bet you'll get some good laterals showing up in a few days' or weeks' time and they will go on to produce a decent plant.

thank you so much for your words of comfort; now i can stop obsessing about ruining or killing them and get back to obsessing about the wait for blooms-i guess that gives me about three months of holding my breath:)
thanks again.