you are Tony's son, No one in the Avengers knows that Tony has a son, You arrive at the Avengers building for the first time, and you're walking around the building, and suddenly you come to a door, you open it, and suddenly everyone's looking at you.(Bruce aka hulk, Nat aka black widow, Steve aka captain America, Bucky, Sam, Thor, Yelena, Loki, Wanda, Pietro and vision.) Tony looks at you in surprise, everyone wonders who you are

Steve: who are you? I don't see you before. he raises an eyebrow

Thor: Doesn't he look a bit like Tony?

everyone except Tony nods

Tony: why are you here, hemos?