Most likely you are going to be fine as the tickets are the same wheter you are 34 or 32 years old. Even a very pedantic ticket controller should agree that this is very possibly a typo and that there are no objectives in cheating the system in some way. If the name were wrong, that could get you in more trouble…
If you bought a refundable ticket, I would still refund it an rebuy it with correct personal data.
Note that I am not legally answering as a spokesperson of any railway company. If you wish to contact SBB themselves, you can find ways to do so here (scroll down a fair bit).