It's not a question of 'ready' as in 'ready, steady, go', it's a case of the fact we are totally unable to support the population with our already extended lifespan, since it has pretty much doubled in the West over the last 100 years.
To increase that more over a large portion of the population would create a demand we simply cannot meet, and to increase it over a small percentage of the population would create an Elitist society that would resented, feared and hated by those not part of it. A situation not a million miles from the situation we face today, but on a much larger scale.
Yes, it will get done eventually, but to throw this out into a world that cannot even support the people who are already alive would create chaos, I'm afraid I've never been particuarly proud of the fact that we as a race view things as 'Just because it's a bad idea, doesn't mean we shouldn't do it before someone else does.'. We have some wonderful weapons based on that exact theory.
As for ethical side of things, true from a personal ethics point of view, it doesn't matter, but what about from a country-wide ethics point of view, if we go back to that tyrant situation, it's not just the tyrant living for hundreds of years, it's the people suffering from it for an equal amount of time, and, since it has already been proved that Superpowers are more than happy to leap in guns blazing in the name of 'ethics', whether we like it or not, they play a role.
Edit: The real irony with 'someone else will do it if we don't' is that, once one group does it, everyone else will follow, so, rather than prevent something bad, it actually propagates it.