Estimated last drug use - am I in trouble

On my SF86 that I recently submitted, I selected “no” for drugs use within the last 7 years because I don’t have specific memory of my experimental use of marijuana extending into the last 7 years. I have experimented with marijuana around 2-4 times and have taken one prescription drug (not prescribed to me). I plan to be fully transparent about this with my investigator during my interview and on the polygraph. However, I had initially estimated my experimental use of marijuana to end just a couple weeks older than 7 years ago (last memory was smoking on my birthday).

My concern is that since submitting my form, I remembered a festival I went to about 6 years and 10 months ago. At this event I was around marijuana, but I do not have clear or specific memory of trying marijuana there. I am nervous though because I remember being around it and my memory is so fuzzy from that far back. I know I was drinking at the event and I know I have never used alcohol and drugs at the same time so I’m assuming I did not use anything, however, there is a slim chance that my memory is failing me. I estimated the last date of my experimental marijuana on my form to the best of my ability based on specific memories I have of actually consuming it/feeling its effects.

I am wondering if this will be seen as falsification? Again, my memory from this far back is so fuzzy. I do not spend time with these people at all anymore, but I’m concerned at the possibility that I could be forgetting something small so now I’m regretting not just estimating with more caution and saying yes to last 7 years since the event was 6 years 10 months ago… but I just don’t remember being high or feeling anything then.

Any advice? Am I going to get get into legal trouble or will this be seen as falsification?

Can you look up the name of the festival and determine the date that way? If so, I would just come to the interview with that information and explain to the investigator that you were estimating the date to the best of your ability, but have since looked up the date of the festival after submitting your security questionnaire. It happens. Just make sure you’re volunteering the info to the investigator before they find out from somewhere else and then it does become an issue of dishonesty rather than just not recalling an exact date from 7 years ago.