Thank you for answering! Did anyone else hear from their teachers about a thank you mail?
Does it indicate anything?
I don’t know about Princeton in particular, but over the years, I have written several LOR for students applying to grad school and I have always received a note of thanks/acknowledgement from the school. (And that was it.)
People I know have received thank you letters for recommendations but had the recommendee deferred/rejected… I wouldn’t get your hopes up, but at least that recommendation reached the Princeton office!