Mmmm ...
I'm with 'helopat' & 'krypton' on this one .... your employer should have insurance to cover this sort of event as a training organisation ... do not get involved in the repair/costs.
"**** HAPPENS" particularly as a (new) instructor .... and this incident is now one of your learning experiences ....
You and your student walked away .... thats the really important bit ... don't stress and don't let this incident affect your instructing negatively.
Good luck in the future .....