Reminds me of Pink Aviator turning back from a solo XC because she didn't like the weather, and was worried that people might think she was "chicken" or something ...
seemed happy I'd decided not to press on if I thought the engine sounded rough
Yes. You made a command decision, that's what you're being trained for. It is never wrong to choose to stay on the ground rather than take off.
A decision to stay on the ground might be unnecessary, but it's never wrong.