You're never too old to change your ways. Learning is always possible. (Compare You can't teach an old dog new tricks.)
Browse entries near It's never too late to mend
it's about time
it's all downhill
it's all over with
it's an ill wind
It's never over till it's over
it's no use
It's not whether you win or lose, it's how you play the game
it's to die
it's to laugh
it's your funeral