The saying is "turn over a new leaf" not life.

"I have been a poor student this year; I need to turn over a new leaf and improve."

He wanted to turn over a new leaf

9.3 Puzzle Time (Geometry)

Turn over a new leaf. Start over. Make a fresh start.

After his stint in Reading gaol, Oscar Wilde was urged by a friend to mend his ways, to turn over a new leaf. Wilde agreed. But a few days later, the friend returned to his hotel suite, which he was sharing with Wilde, and found Wilde apparently doing the thing which has no name with the bellboy. Shocked, the friend remonstrated: "But Oscar, you said you would turn over a new leaf." To which Wilde replied, "Yes, but I haven't yet gotten to the bottom of the page."