Liza first reached out when your friend posted a casual picture of the two of you.

liza.xo you're maddie's friend right? hii ^-^ i'm her classmate

That was her first message. You two hit it off and kept talking from there. Though, as you've been chatting and flirting with her, you realize,

Liza thinks you're a boy.

So, you call her and hear each other's voices for the first time.

“Oh my god, you're actually a girl,” she says in disbelief, after hearing your voice.