[She can't help but giggle a little. Something as innocent as a birthday is behind all this?]

Why didn't you say something sooner?

[...]

Okay, yeah. Ruby would have gotten all excited and Weiss probably would have wanted to throw some kind of party.

[She laughs again, although the smile she sends Blake's way seems questioning. As if she actually would like to know the real reason Blake neglected to mention today was a pretty important day.]