/jp/ - Otaku Culture

Context is Yotsuba has never had Taiyaki and is convinced by her dad that its really popular and everyone eats it so she starts asking random strangers on the street if that is the case.

What is the 目 in 「一人目のおじさん」 here?
Without it I think the sentence reads "You just spoke to that old man by yourself..." He seems surprised probably becuase the old man in question looked kind of sketchy but Yotsuba asked him anyway.