I think they just met. But how he addresses her sounds very casual, calling her by first name. Is it common to do so?

Rebecca

Yes, it is common to address people by their first names when you first meet them! Especially if you meet people casually like this and are both considered 'adults.' Sometimes at work or school, people prefer you call them ma'am, sir, or another title. But even in universities, it can be common to address your lecturers by their first name. And it does sometimes depend on what one was taught growing up or where someone is from. Ex: Nice to meet you, Mary. I'll see you later. Ex: Oh, please don't call me 'sir.' Call me 'Shaun.'