"I did my best, and the residents seemed to really enjoy it." - that's the only thing that matters here. Even if you had been terrible, and they'd been enjoying it because they were laughing at you, it'd still be the only thing that mattered, that they enjoyed it.

As it was they probably got a lot more out of it than if you'd been some really experienced virtuoso who was doing it as a chore and didn't really give a damn for the listeners.