[Vastra isn’t wrong about Pepper’s confusion, no.  But some other details have gotten mixed up, and she shakes her head.]
 
Oh, no.  I wasn’t here then.  I got here about two months after that happened.  [Although it’s not hard to see what she’s getting at, and she tries to offer a different way to answer the question.]  Tony had been here about a year at that point, though.