Zoro is nineteen years old at the start of the series.
Let that sink in for a bit. Yes, it’s a fantasy story and typical shonen kid hero rules apply, but I think it is helpful to take both Mihawk and Zoro’s age into account when breaking this down.
Zoro is ultra committed to his dream, but he’s just starting out. He’s enough of a realist to know that a goal as big as his is going to take some time to accomplish. And, really, he’s not in a rush. Not so long as he stays on the path of a swordsman. There is literally nothing from stopping Zoro from taking one look at Mihawk, realizing he’s got a few more levels before this is an appropriate encounter, and waiting to challenge him when he’s more up to the task.
But he doesn’t, and at this point in the series his pride and the weight of his promise to Kuina demands that he can’t.
(Obviously that changes, but we’ll get there.)
From Mihawk’s perspective, I imagine that he gets “challenges” like this all the time, and part of his responsibility as the World’s Greatest is to answer them. He could easily brush Zoro off, but he does duel him–albeit in the most condescending way possible. Mihawk is forty-one and has been around for awhile. He gives the impression in these early chapters of being bored and apathetic to the world around him. It’s only when Zoro captures his interest that he does things like go to Warlord meetings or catch up with Shanks to talk about some weird straw-hatted kid he met in the East Blue.
