Hello Ghettamouck45
Do you think it was you who made this mistake?
I can tell you that the SBB ticket shop has currently the bad habit of changing entered dates by one day, to the surprise of the person buying the ticket. It happens very rarely, but the technicians are looking into it.
When do you intend to travel? If your trip happens in the next day, please contact the SBB Contact Center by phone to rectify the date of birth, the team there is informed about the technical glitch: +41 51 225 78 56 (from the U.S.: 011 41 51 225 78 56). If the trip is scheduled for next month or later, you can also contact SBB by using the contact form:
https://www.sbb.ch/en/help-and-contact/customer-service/praise-comments/reklamation.html
Please let us know about the outcome.
Kind regards,
Roland