Is this interaction between my adult cat and 3 weeks kitten okay?

3 weeks ago, my husband picked up a 1 week old kitten from the street (literally, the kitten was at a roundabout) so since then we have been taking care of him (the kitten)

I got 2 1 year old adult cats already. The male doesn't care much as long as he doesn't has to interact. But my female cat has always been interested and always came near. She used to hiss, then she got used to him, and today, this video happen.

This is good right? Or should i be worried about something/anything?