I appreciate the feedback but I'm really not sure what isn't lining up for you. I never mentioned any depression, only a slow realization of what happened. Celestia does
attempt to comfort Twilight, but nothing she can say could actually help.
Twilight growing wings didn't make her a princess. Celestia showing up and telling Twilight
she's a princess, is what made her a princess. Just imagine if she hadn't done that. Even if your interpretation of the subject were true, she'd never have been coronated except for Celestia's direct choice. And even if somehow there were more to it than Celestia's individual decision, what's important is Twilight's own perception that the only reason she became a princess was that Celestia told her she was. Right?