Go to EB\Data\Scripts\showme\EBBS_SCRIPT.txt.

Search that file (ctrl+f) for section 2c.

Look a few lines down for and I_TurnNumber > 120 (that's the polybian counter... Look under the Marian section for a similar line to change those) and change that turn number to whatever turn you want. Remember to divide the number of turns by 4 for the number of years.