Can i get a tattoo to cover my defibrillator?

No: I'm not an electrical engineer, but I think it's a bad idea. If you insist, you may receive an inappropriate shock from your device. Even worse, it may be reprogrammed, so be sure to have it fully interrogated immediately afterward if you proceed to assure that you're fully protected. I'm in my 60s too so as one older man to another, consider discussing your self-image concerns with a counselor.