I'm not sure who I am to have opinions. I have one child, a first grader, so I have no idea how our decisions will play out in the future. All kids are different, of course, but I do see some disadvantages. I was born three months before the cutoff and always did best socially with kids two grades younger than me. I spent an extra year in college on purpose. (My parents had no idea what I was doing.) I stayed for the social experience and so I could take more classes that I didn't need.
I think that social experience is a really important aspect of education for a lot of kids. I'd rather that my child get that from the start, rather than "flunk" herself in college (with my money) so she could spend more time in the cocoon.
My kid has poor motor/coordination, is in that perfect highly successful zone with math, has to work at spelling and some grammar type skills (not much, but some), and is way, way ahead in reading and the knowledge acquisition that comes with reading and being interested in things. She doesn't crave math on her own, so she does what the school tells her to do. If they told her to do more, she'd do more, and that would be nice, but it would take more work. And if she really had to struggle with writing and spend more time with math, spelling, and grammar, would she still have time to follow her interests, the areas in which she might have true talent?
I can see how there might be a lot of advantages in moving up a globally gifted kid or a mathematically gifted kid. But my child's science, reading, and history interests wouldn't be met by moving her up a grade or two or maybe three--and she'd be way out of her league in the writing and social areas.
A few minutes ago my husband texted me from the bookstore. They have been there for almost three hours. He says she's reading all the books about Hanukkah and doesn't want to leave until she's memorized the Hebrew alphabet. If we moved her up, making her less socially successful and giving her a challenge in math, would she lose time to explore her own interests that still wouldn't be met in school? For me, that would be the major disadvantage in moving her up.
We're trying to achieve the growth mindset that gifted kids don't usually get to experience through music lessons, and we never use the word "gifted," downplay "smart" and talk a lot about hard work. But in many ways, I think the fact that she needs to work less at school does allow her more time to persue interests.
