On the contrary, the phrase "not so different from you after all" does yield multiple results. Examples being:
Zuckerman, E. B. (2006). Growing Up Different by Bonjenji (p. 222). iUniverse.
It's a shock, actually, to discover that others are not so different from you after all, that they have feelings, also, that they very rarely express, and then to get the return trip realization that [...]
Arden, S. (2014). A Glorious Christmas (p. 4). HQN Books.
India shook her head and continued, “I guess I'm not so different from you after all,” India volunteered. “I'd convinced myself that happy-ever-after wasn't real, but I've been slapped in the face with it so many times in past months that I can't ... [...]
O’Connor, J. (2008). Have Your Wedding Cake and Eat It, Too (p. 108). Thomas Nelson Publishers.
It turns out that the person you wanted to be wasn't so different from you after all. It's never quite the same, or you wouldn't write another poem, but it doesn't have to be that outrageously different. You find that out, but only after years and years ...