Was it a tiny little plant or a plant of some size? If it had some size on it, it may have been more than a year old anyways.

As a rule, I don't prune young perennial plants (outside of mint, oregano, and lemon balm) until the second year. In the second year, I lightly prune. But if the plant is very vigorous, I may harvest more. It's the third year that I prune and harvest as much as the plant will take. I try to give the plant time to establish itself. I want to harvest for many years as opposed to one.

Each plant is different. Some not only tolerate but become more vigorous being cut back to the soil line. Others you have to have a far more gentle hand with, pinching leaves and buds judiciously by hand. Learning what is best for each plant *before* cutting will increase your gardening successes.

All that said, I never prune my lavender. It may need on occasional a light clip to neaten it but never a pruning.

FataMorgana