no it is not yoga, but many of some of the postures the girl takes are in fact
yoga positions, or begin as yoga positions.
Yes , she would be properly termed a contortionist,
which again comes from years of very focused training with body muscles.

I looks to be a girl about in her late teens at most, tho probably younger.
I am certain she has spent many years developing her skill.

She seems to be at a demonstration or even a competetion event.
(notice all the kids lined up ready to put on a show in different costumes
behind her?) so she may infact be a kid, and she has been trained well,
and looks a bit older cause she seems to be taller than they. ?

It might be a *amateur talent show* even