First, I like the chapter, even though I'm not big on X-Men and I'm even less on tragic childhoods and abuse. Still, sounds pretty good so far.
A few things, though. Putting FLASHBACK right in the middle of the story breaks the suspension of disbelief--it pulls the reader out of the story. It may work better if you can put the memory into a dream or, better, not use it until absolutely necessary, if at all.
Next, you use a lot of passive voice, that is to say a lot of "was", "weren't" and "had been". It's been my experience that the passive voice weakens stories. Case in point, "The wind was blowing." That doesn't create the same picture as "The wind tossled her hair gently," or "The wind cut through her like a knife." It just makes it a little more... real.
These are only suggestions--don't feel that you absolutely have to take them. I hope I was able to help you some.