Translation:I have a date this Saturday.
A date? In English, "a date" only applies when meeting someone with the possibility of a prospective amorous relationship. For instance: "I set up a date for my sister with my friend Alan ." Is that what "约会" mean? That's news to me . . . A date of this kind would be: "约会对象." The one here is "an appointment."
I'm guessing it's a (romantic) date since it's in a Saturday and we already learned the word for romantic. Fits better than an appointment, doesn't it?
It is funny how in the earlier parts of this course it does not let you say 'this Saturday' when comes to a future event. You get marked often wrong because they want you to say "next Saturday" (or whatever future day they write).
But now in this part of the Course it is always 'this Saturday' or whatever day.