It really is surprising how many students have told me something akin to what this particular writer has said - usually some variation on that or "I've always gotten A's in English." I'm really baffled by what they think telling me that will accomplish.
Ironically, it's usually the best writers who tell me they're struggling, who tell me, rather shamefacedly, they're really dissatisfied with what they've turned in to me and that they know they can do better. In fact, three of my four A/A- students this quarter said as much to me this past week.