Go to the vet. Ask vet for the correct dose of the vaccine for you, including the tooling to administer it. Administer the vaccine yourself in the vet office. P

Go to the vet. Ask vet for the correct dose of the vaccine for you, including the tooling to administer it. Administer the vaccine yourself in the vet office. Pay the vet. Come back at the right time for the booster dose. There should not be any difference in suitability between the vaccines, but you might want to check if the same style of vaccination (i.e., kind of disease and procedure of deriving the vaccine) is used for both humans and some animal the vet would use the vaccine for if you hadn't come. You might do that with a different vaccine, but there isn't much difference between mammalian vaccinations.