Oh no. She hated lying to Lois, but "oops, I spilled my secret identity and also he's a speedster so we raced to Paris" was probably going to earn her a stern talking to if not worse. Maybe not from her, but from Clark. Plus, she couldn't compromise Bart's secret identity. Obviously Lois was trustworthy, she was surrounded by this sort of thing, but Kara felt there was still a certain amount of privacy and respect due. That and this wasn't the kind of thing to discuss in public over tortilla chips.
"I know you're not, you didn't come to my apartment with a huge frowny face. But it was totally just sandwiches," she smiled, hoping Lois would get the message, "but I think we might go out again soon."