[He visibly flinches at that and seems to think back on what he's saying.]

It means that...

[He needs to think before he speaks. Clearly. He's not dealing with an audience who knows what he's talking about and how long has it been since he's done that?]

The things I've forgotten, or the things that mattered to me when I was...younger, it's been seven or maybe eight years since then? So it's a long time.

[He's not even sure how long it's been. Wow, time has really flown.]