Sasha Cohen's jumps were tiny too and she managed a quad a few times (in practice).
Sasha Cohen's jumps were not tiny. She got similar height to Michelle Kwan which is average. Yulia's jumps are tiny indeed. When her breasts and hips develop she might have a very hard time sustaining their consistency.
This is the only woman recorded to have nailed clean, fully rotated quads in practice: http://www.youtube.com/watch?v=xR68Q4X45hg