Oooh, that is angsty! But it's quite good - you've captured the sad, almost devastated side of Petunia that we don't often see. Usually we are just left with her bitterness: this shows her anger and heartbreak as well, over both not having magic and losing her sister to it.
I thought your language and the form was great, although the 'thine' did jump out at me as not quite fitting in with the rest of the poem. Mostly because you use 'my' and 'me' and 'your' and an old-fashioned 'thine' doesn't fit with them. I'm guessing you don't want a 'my' there, though, so maybe 'these eyes'? Just a suggestion, hope I haven't offended!
Lovely (dark) poem!
Author's Response: Thank you so much :) I'm not sure why the thine was put in there; I thought it kind of gave it flair. I'm a theater kid, though, so flair i everywhere for me, lol. But I'm so very glad you enjoyed it :)
Again, I just loved this poem! It is so wonderful! I cannot fault it!
Author's Response: Yay! *Bows down low* My deepest gratitude, my dear.