Ok, let's take this from the top.
-- Getting married on a GC is fine. You are allowed to.
-- Lying about getting married at any point in the process is not fine.
When you got married, did she apply for a student visa after the marriage? If yes, did she say she wasn't married (that is an issue).
If she just got a student visa on her own, that's fine. If she was not married and said she wasn't married, that's fine too.
Now, as for you --
- did you file your N-400 that you were not married? That would be an issue. I would suggest being extremely honest here.
One alternative is to get a US civil marriage and then use that as your marriage date. But you have to be honest. DO NOT stay silent through your citizenship -- you are getting your citizenship with factual inaccuracies that could come back to bite you.
You should also probably speak to a lawyer.
-- Getting married on a GC is fine. You are allowed to.
-- Lying about getting married at any point in the process is not fine.
When you got married, did she apply for a student visa after the marriage? If yes, did she say she wasn't married (that is an issue).
If she just got a student visa on her own, that's fine. If she was not married and said she wasn't married, that's fine too.
Now, as for you --
- did you file your N-400 that you were not married? That would be an issue. I would suggest being extremely honest here.
One alternative is to get a US civil marriage and then use that as your marriage date. But you have to be honest. DO NOT stay silent through your citizenship -- you are getting your citizenship with factual inaccuracies that could come back to bite you.
You should also probably speak to a lawyer.