Help me save face!

[ShoutyMom]

After a 4 year break to be a SAHM, I've recently started teaching part time (different career path altogether to my previous jobs in banking). I wrote tests and did interviews, so the selection process was reasonably robust, and they provided me with training as well before I actually started teaching classes.
It is a sort of prep school (not in UK) for people who wish to go overseas for higher education, and have to write exams such as SAT, GRE etc. The students are young adults, most of them have full time jobs and do evening classes.
In my last class, one of them disagreed with my response to a particular question, and we discussed it a bit. I started to think I might be wrong, but stuck to my guns and finally said "look let's come back to it later, shall we". Well the next class is 2 days away, and I've realized that I was wrong and he was indeed correct. I am not too proud to accept my mistake but worried that I will lose all credibility with the entire class. How can I correct my mistake without looking like a complete idiot?

I'd be upfront and honest, and I'd smile a lot. It's ok to be wrong, and your students would likely respect you more for being upfront than hiding it (especially if they could look this up themselves). Adults know that we're sometimes wrong, and won't think that you're a complete idiot. Can you start the clas with it? Can you make it into a useful learning 'opportunity'? (I cold my think of a less wanky term, I'm sorry) i think if you can demonstrate why you are wrong, or what can be learned from the error, then your students should find it an understandable error.

Yes, the whole smiling and energy thing is an action point any way for me. Right now I feel my delivery is a bit stilted and bit of a monotone, partly because I feel sooo conscious standing up there, and under pressure to know all the answers.
This was an English Grammar ques so a bit difficult to spin it as an action point but I'll go overall with your suggestions. I only hope they don't all queue up outside the office the next day and ask for a different teacher!

• spin it as a learning point

One of the ways that you can sometimes tell that a fluent speaker is not a native speaker is that the grammar and vocabulary is more precise and accurate.
I have a couple of friends that speak the best Queen's English I've ever heard, neither of them have English as a first language.
You'll look more foolish if you don't just 'fess up and explain why you thought differently, and that as a native speaker, it's easy to forget.

I would embrace it and prepare a little thing about WHY he is right, and why you thought you were right, and where that error can also occur in similar situations.

Hag, unfortunately I'm not a native speaker, though I do (usually!) have excellent English and am completely bilingual.
Golf and Callamia - thanks, I'll definitely try that route.

Be very gracious to the person who was correct, don't be embarrassed or shy away from addressing your error.

Start the class with 'I've had a bit more time to think about what Jeff said the other day and I've realised that he is correct, a sentence should always start with a capital letter (or whatever it was), so thank you Jeff for pointing that out. Let's make a note of it...' then move on to the topic of the day.

Thanks noble!