I've had those same worries too. When Peter was learning to stand/ walk, he clunked his head so many times, and he kept on trying. I had a admire his persistence!

All I can say is, they do actually learn fairly quickly and they don't hit their head (at least on the floor) as often after a while.

Just be aware of the signs of concussion, and if your little one isn't showing those, then she's probably fine, and let her get on with exploring!