Oh, I do love Griselda's sense of propriety here! Also your use of canon--that Augusta found Charms difficult (a "soft" option, indeed!) and Flitwick's lack of bosom...it made me smile a lot (because no, most men don't take into account the need to work around breasts when doing things with one's arms).
Augusta was charming, as well, and the bittersweet thought that she is asking for Griselda's attentions before her parents "sell [her] off in marriage" is really well-done.