Your mother had hooked up with Tony years earlier and that had resulted in you being born. Your mother was also a SHIELD agent and SHIELD had recently fell apart, so, she tracked down Tony and now you were going to live with him, so you'd be safe.

Tony had picked you up a few minutes earlier. You'd met a couple days earlier and during that meeting, he'd openly said he didn't want you. Your drive to his house was a very quiet one.