You've made an error.
I can't offer any thoughts about the way the FAA approaches such things but we are all human....and we all make errors.
Assuming it was an honest mistake - and I'm not suggesting it was anything other in this instance - I would expect an investigation to be carried out. The objective of the investigation should be to find out why you were able, or even encouraged, to make the error so that we can all learn from your experience and, ideally, make changes to the system to make others less likely to do the same thing.
This may - and, ideally, should - mean that someone from an investigation team comes knocking to ask you for your perceptions etc. Questions that might be of interest are what training you had on the topic of airport layout, were the ATC instructions clear, were the makings/signage clear....and so on. Unfortunately not all incidents are fully investigated but you might like to think about whether any of these factors contributed to your error so that you can share the information with others locally if nothing else.
I wouldn't worry too much about FlightPathOBN's comments. Be honest - with yourself and anyone else who wants to know what happened. Hopefully that will be the end of the FAA's interest....and if that's the worst error you make in your aviation career you'll have done better than most!