The eye description brought me up short, particularly in combination with the race. I guess it depends on the precise racial mix, but brown eyes tend to be more likely to be inherited genetically than blue eyes, as far as I know. So, not impossible perhaps but not especially likely. Also 'silvery blue' sounds both metallic and non-human, which might work for a non-human character but that's not the case here. If you really mean greyish-blue, it would be better to say that.
As for the Mary Sue issue, I can never tell from a bunch of stats alone - I have to see the way the character turns out in the actual story. Absolute perfection can be a pointer, every character loving them (or hating them) without exception can be another, and if there's one thing that screams Sue to me more than anything else, it's a description of how incredibly talented or how beautiful they are on virtually every page. I'm actually less inclined to think it based upon background. I have read about characters with incredibly Sue-ish backgrounds who came over as interesting and engaging in spite of that, and I have also read cardboard cutouts of that kind too. It's good to have flaws but don't go completely overboard as it's just as easy to create a cartoon villainess type as it is Princess Perfect.