That’s how it is for us as well. My dad started the business in 1980, but he can’t narrow it down further than that. I started working there some time around when I was 12, but I can’t tell you the first time I punched a clock. To make it easier for everything, we picked a day in 1980 and use that as our ‘first day’ in business. Similarly, I use my birthday in 1992 as my ‘first day of employment’. We quickly found out that picking a day and always using it makes life easier. It really doesn’t matter if we opened on March 17th or August 12th of 1980, but if you give one answer to the bank when you get a mortgage and a different answer to the SBA when you want a loan, you might get called out on it.
It’s kind of like the security questions you get asked on websites. You really don’t have to know who your favorite teacher was, but if you always write Mrs. Crabapple, the website won’t care or know that you made it up.
I assume the question is going to be something verifiable, like if they’re asking when you started with your employer, they can compare your answer with the first year a W2 form was filed by that company.
Seriously, though, they know that not everyone remembers every little detail. So I assume they will understand if you’re vague or unsure. (On the other hand, answers that are too well-rehearsed might seem suspicious.)
A few years ago, my business manager made airline reservations for me to attend a seminar. My flight to Arizona went fine, but returning to Pittsburgh a TSA agent noticed my middle name on my boarding pass was spelled “Steven” instead of the way it is spelled on my driver’s license, “Stephen”. He began making a big deal about it.
Meanwhile, I was laughing it off. He glared and said, “you’re not necessarily flying today”. That sobered me right up. He detained me long enough that I had to run to my gate.
I recall being given one of those online verification tests for something, and all the correct answers were “none of the above”. I apparently didn’t have enough of a credit record or vehicle history to be checked against, as everything had been in my parents’ names for most of my like, but I suppose it’s also possible that I randomly was selected for 3 “none of the above” answers independently. I took one several years later and at least one of the questions had a correct answer; by then there was more establishment of my own identity.