It sounds like you lucked out with that one. We regularly accept non-refundable deposits with usually a 2 week timeline for full payment. I've found most people are excited about getting their new animal though and payoff as soon as possible.
Sounds like good advice above but I just want to add that if you offer a non-refundable deposit again, be sure to highlight the non-refundable part in an individual email as it prevents any confusion from a customer not reading the terms on the website.