[PeterisP]

This is a situation where it's important to believe what is actually true.

If aging can't be stopped, then it's appropriate to accept your mortality and not be in denial.

But if aging can be stopped, then it's appropriate to fight against your mortality and not accept it.

Accepting your mortality has always been the correct answer because (and only because) we always have been inevitably mortal, and denial about mortality has been bad because (and only because) it's detached from reality. However, once the reality changes and it becomes plausible for the people living at that time (perhaps this time has already come for people who are still young? who knows) to become effectively immortal, then refusing to accept mortality stops being denial and becomes a healthy attitude.