Hey, it's okay. Gwen wouldn't have known who a lot of famous people were simply because she didn't follow those circles. He wasn't alone. If he wasn't into somewhat geeky things or didn't... y'know... look at the covers of Forbes magazine? He'd have no reason to know who Tony Stark was.
"I really liked the Crepe truck." Gwen said, grinning softly. "And there was a Thai Food truck out here for a while... man, I miss the Thai Iced Tea."