Most places require you to show proof of age. Or require you to bring a parent with you. There are laws that can be broken and lawsuits to be made if a tattoo business or even a single person who does tattoo's on underage people. Your best bet is to just wait until you become of age to get the tattoos. You certainly don't want to get a disease by going to some back-door place or someone who you are not sure of their talent and credential's. Better to be safe than sorry.
I too would wait. They are permanent and SOME people (like me) end up regretting tattoos that they got prior to being of age. :/