연세가 어떻게 됩니까? is correct and honorific enough !
But we mistakenly use it like 연세가 어떻게 되십니까? to make it sound like super honorific which is not correct grammatically.
Plus, to make it more natural, this is used more often "연세가 어떻게 되세요?" and this is honorific enough, too!:D
Hope it helps !
(We don't use honorific form makers like ~께, 께서 to non-living things(like 연세 here)