It's not recommended that you vaccinate a cat until it is 8 months old or older.

 CONGRATS ON THE NEW KITTY! Your kitten should be taken to the vet at 3 weeks old for its first deworming, then when it is six weeks old it will need to go in for its feline lukemia test and first set of vaccines. Every three weeks after six weeks old it will need to go back to the vet for its other sets of vaccines. Six weeks, 9 weeks, 12 weeks and 16 weeks it will need vaccines. At 16 weeks it will get its last set of vaccines that will include the Rabies Vaccine. Make sure if the cat is a outdoor cat that it gets its Feline Lucemia Vaccine. Cats that are strictly indoor and never go outside do not need that vaccine. After 16 weeks old you can get your baby either nutered or spayed. This is very important because there are so many stray animals running around in this world, especially little kittys. If you have a male and don't get him nutered he will begin to spray your house in a act of dominance. If you don't get the female fixed she will surely come back pregnant or you will have to hear her cry in pain when she goes into heat once a month for the rest of her life. Over all getting your animal is fixed is the best way to take care of and prolong your kittys life.

 It doesn't matter how old it is if it needs its vaccinations then take to a vet