"I won't," he says at once, still sounding slightly dazed. Then, calmer, "I promise you."

After a few seconds of opening and shutting his mouth around several different sets of questions, Steve finally manages, "How? I mean, I'm sorry, I'm not trying to be rude, I just thought- Even JARVIS doesn't- You have a body, right?"

He winces again and waves one hand in a desperate negative motion. "That was rude. I apologize. I just... Technically?"

He latches on to the one thing she said that can obviously be expanded on, trying to get his brain back on track.