past it
• too old to be of any use or any good at anything.
• "he was taken into his father-in-law's firm and became a partner when the old man got past it"
Similar:
past one's prime,
not as young as one was,
not as young as one used to be,
in one's dotage,
long in the tooth,
as old as the hills,
elderly,
old,
aged,
senior,
ancient,
venerable,
decrepit,
doddering,
doddery,
not long for this world,
over the hill,
no spring chicken,
senescent,
