What are the cons of tattoos?

I am 15 going on 16 in a few months and I really want a tattoo. I want a symbolic one on my right shoulder blade. Im not sure if I want to get it yet not because Im unsure if I want it but just because I don't know If I want a tattoo in highschool. So what are the cons of tattoos I heard that certain dyes are known to cause ink poisening and such. Also what do you guys think?