Tetanus is a rare but very dangerous infection caused by a bacteria that lives in the dirt. The mortality rate from a case of tetanus is very high; for these reasons, everyone should be vaccinated against the infection. The tetanus vaccine only lasts about 8-10 years, so it is necessary to have a repeat vaccination at least that often. You shouldn't wait until you have cut yourself with something dirty to get the vaccine, because the vaccine works better if it is done before a potential exposure to tetanus rather than in the moment of the injury
Furthermore, there might be another reason to have a tetanus booster now. There is a form of the tetanus booster that contains a pertussis booster vaccine as well. This is called Tdap. All adults who have not had a pertussis booster should have one, since immunity to pertussis wanes over time and the incidence of pertussis in adults is on the rise. Therefore, this might be an opportunity for you to get the pertussis booster as well as the tetanus booster in a single shot.
Talk to your primary care doctor
about this again; they can set you up with another visit to get your shot.