Who said "I learned that my past doesn't define my future."?

This quote is attributed to George McFly.

I learned that my past doesn't define my future. - George McFly

"I learned that my past doesn't define my future."

George McFly Hope

"I'm your density. I mean, your destiny."

"This is heavy."

"There's that word again, 'heavy.' Is there something wrong with the Earth's gravitational pull?"

"I'm not very good at science."

"Every day is a new opportunity."

"Hope is what gets us through difficult times."

"I'm not your enemy, kid. I'm trying to save you."

"Redemption is a long road."