Do you remember your first callsign? Presumably a 3-land one if you tested at Laurel, MD. You can then look up various years of paper callbooks (hamfests a good place to do it) until you find the edition you first appear in, then you know it was that year or the previous year.
Because novice callsigns were sequential it may be possible to narrow it down further (nearest month maybe) by comparing with known issue of other nearby callsigns.