#breadstix

I've seen people view it as Santana’s panic surrounding them dating causes Brittany to panic too and that she was like "isn't this a date!?" because she was worried they were on different wave lengths.

A different take that other people have is that Brittany hasn't really thought about it up until that point when Santana has brought it up and she's asking the questions in the moment as if to to be like "well does this count as a date? can we say we're dating now?".

I personally see it differently. My opinion has always been that Brittany's answer is sarcastic almost, like she's trying to be like "of course we're dating! we have been all along!" and she's been viewing the whole time since she split with Artie as them dating, since they've been doing couple-y things like taking baths together. It kind of fits with the narrative that Brittany has been waiting for Santana all this time, so when they're both single it's just obvious to Brittany that they're dating, while Santana needs verbal assurance on it, but Brittany waits for Santana to be the one to make that call so not to freak her out. 

Then when Santana finally does have the courage to label it, she answers in that way because again it's a soft way to answer such a daunting subject for Santana. Just to reassure her and be like "honey don't worry, we have been all along" rather than have a big serious chat about what they are etc. They didn't really need to have that since all the feelings had been put on the line months before, and the only thing stopping them being together was Britt being with Artie (who I think she was hesitant to break up with knowing Santana wasn't fully ready yet but that's another story). Brittany even says herself that she told Santana that if they were both single they could date, as if it should be obvious to Santana that they were together and she didn't need to worry about it, and Santana's relief as soon as Brittany answers with "wait, isn't this a date?" adds to that narrative as well. Like she's instantly reassured.