My daughter fell straight down on her feet & jammed ker knee. Has full mobiliy. Is she ok?

Fell on her knees. If she has no pain, no swelling and is walking without any discomfort or pain then she is alright and do not need any medical attention.
Yes. I agree with dr. Khanna. In that case, she does not need medical attention. However, injuries to the cartilage inside the knee does not always show itself until later. If she starts to have difficultly down the line, the source may still be this injury.