She may, perhaps, stop widening the gap between her and the brightest of her classmates in maths - but you're giving her something more valuable than the chance to be ahead in maths, viz., the chance to work hard at it. That experience may be more important than her IQ in shaping her achievement. She's lucky.
Compared to many round here her IQ isn't super-high, but there's a reason why that two sd above region is sometimes called "optimally gifted"!
My DS is ahead in maths and one of the ways I find most helpful to think about this is "he has time" - he has time to explore things of interest and to revisit a topic if that seems useful and to spend plenty of time working on problems. The prizes aren't for reaching the end of school maths sooner but for coming out the other end able to make maths work for you.
