I will also add that I wouldn't hold back a gifted kid for maturity reasons unless you are sure that your gifted kid is not within the range of maturity for that grade. There is a ridiculously huge range of maturity in the early grades. GT kids may stand out more because a teacher might see how much they can do academically and subconsciously expect them to be better behaved. But GT kids are like all kids -- they come with a variety of maturity levels. In all likelihood, they are within acceptable range
