We've had girls in third grade here starting their periods. As she gets older and everyone around here hits puberty, they'll be shooting up. So she's a taller now - pfffttt. Each year - heck, each sesason - that is going to be less and less of an issue.
If you start jacking w/her age now, you're going to be explaining it - calling more and more attention to her.
I'd leave it alone. I'll bet it's a non-issue in less time than it'll take to try to "fix" it with far fewer repercussions.
But that's just me.
Becky
The Woodworth Family in Beautiful San Antonio TX