By the time I'd made it to the music room I could hardly breathe, let alone teach!
I must admit I made a less than impressive noise on the little cello as I adapted to the differences. Where you put your hands, and the spacing between the fingers is all entirely different. Luckily the student ( a sixth-former) was amused by my horrible intonation, and occasional running out of bow (half-size cello, half size bow) as I played scales along with her in the lesson.
Looking at this, I should be aged 7-11 and just over four feet tall. That could explain a lot!