Tattoo??

Ok. So I'm on day 45 of my cycle. I went and got a pregnancy blood test last week and it came back negative. We had TTC sex on Sunday night and I think I might be ovulating today. I've got an appointment for a tattoo on Saturday (which I made after getting the BFN)... It should be safe, right? If I did manage to get pregnant off that one shot, it'd only be like... 3 days along?