The age that you have to be to get a tattoo varies from state to state.
More Info: Tattoo age requirements are regulated on the state level. Most states require that you be at least 18 years of age to legally consent to a tattoo but that's not always the case. Currently South Carolina requires that a person requesting a tattoo be at least twenty-one years of age. Many states allow a younger person to get a tattoo with parental or guardian consent, but this age range also varies from state to state. South Carolina's minimum age for parental consent is eighteen while Oregon makes no exceptions for parental consent.
If in doubt check with your state's official government website.
Why Such Stringent Age Requirements?
Legislators are looking out for the best interest of youth. Tattoos are permanent and are not a decision to be made lightly. An anarchy symbol tattooed on your cheek as a rebellious teen might seem like a good idea today, but what happens when you decide that you want to run for president? The example may be overly dramatic, but emerging studies are suggesting that people with conspicuous tattoos may be, or perceive themselves to be, discriminated against.
In a study of women inmates who had received tattoos in prison, many claimed that they found the tattoos to be a barrier to employment after release.
According to a study published in The British Journal of Dermatology, 71% of participants requesting laser removal of unwanted tattoos had gotten them at an average age of sixteen. Most admitted the tattoos were applied impulsively and had regretted the decision for decades perceiving the tattoos as creating significant psychological, social, and financial burdens.