I think Mistral is too dark for Ginny. I always thought of that as Sirius' handwriting. Bradley Hand ITC fits it better - it's not too girly, but it doesn't look messy or anything, and after all, Ginny IS a girl, even if she's not all pink and fluffy.
Speaking of pink and fluffy - think of Arnold. A girl who "aaaw"s at such a creature wouldn't write in Mistral
If you don't have these fonts, here's a picture for you: