Themes
Grow old along with me! The best is yet to be, the last of life, for which the first was made.
— Robert Browning

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Growing older is offered as a shared prospect with something still to look forward to. The later part of life is given purpose, rather than treated as an afterthought. The invitation makes companionship part of that confidence, asking another person to remain alongside the speaker.
Context reviewed