Its a shame you have to be intimidated and coerced into doing something you dont wholly believe in.
The JWS is a piece of shit religious cult no question and its no blood doctrines has killed thousands over the years, my mother being just one.
To paint a theoretical situation if your pressed to sign a no blood card you could do so now and when and if there comes a time you could accept one in a medical emergency, health officials at hospitals will act accordingly to your wishes, not what some outside religion presses to enforce.
You could also just say your not ready to make that commitment, of course this is all dependent upon if your baptized or not, if not then they will leave you alone but if you are they may take other discretionary actions ???
Being ostracized for a little while by some cranked up elders is better than being dead and needlessly dying over some foul devised doctrine by someone who wasn't even a true bible theologian, as is the case with most if not all leaders of the Watchtower Corporation.