Welcome to Bike Forums. Nice looking bike.
I'm 5'-11" and my bikes are 54cm and 56 cm. I hope the 59cm isn't TOO big. Did you go to a Bianchi shop to at least do a stand-over fit?
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.