If you also plan on teaching html and css, than I’d go for js first. Having your code instantly response in a visual way, is super motivating for most students.
If you just want to tech programming concepts, i’d go for python.
If you want this to be the start of a complete cs study, than you can start with C

That makes sense, I am also teaching html amd css first so I think JavaScript makes sense to teach next.

I was thinking about C because that’s the first thing I learned in the college and that’s my favorite language till this day.