On is never too old to learn. http://www.mdbg.net/chindict/chindict.php?page=worddict&wdrst=0&wdqb=%E6%B4%BB%E5%88%B0%E8%80%81%EF%BC%8C%E5%AD%A6%E5%88%B0%E8%80%81

live and learn.

one is never too old to learn

“活到老，学到老” Live to a ripe old age, learn to a ripe old age. or The longer you live, the longer you have to learn.

There are many ways to say. 'Live till old, learn till old" "Never too old to learn" "live and learn till old"