My theory is that if anyone experiences an afterlife, it is of their own making, in the few minutes before brain death. It's like dreaming. Time, and the way you experience it, becomes distorted in dreams.
People can dream hours, days, even weeks in a matter of a few seconds.
Our brains make up long dream sequences in a split second to explain outside stimuli while were asleep. I think something similar happens as we lose consciousness just before death, only far more powerful. You can dream of millions of years in whatever afterlife you expect for yourself in the minute or two it takes for the electrical patterns in your brain to fade. Sure, it's not eternity, but it's close. For people who die violently, and get their heads blown up, well, no afterlife for you.