How long will be the "lifetime ago"?
A "lifetime" is the total length of someone's life, so a "lifetime ago" refers to the amount of time ago in which an average person lives. This expression is often used as an exaggeration to mean that something happened a very long time ago, that it feels like it's been an entire lifetime. Ex: Seems like a lifetime ago since I've been in an airplane. Ex: I smoked a lifetime ago.