What if, in terms of academics, I am taking away an advantage of being the smartest/close to smartest kid in the room and therefore be ahead in competing for the spot in a good college and moving her up bringing her more to her true academic pears will be too competitive for her since this is an academic magnet where kids already selected based on achievement.
Based on my personal experience, I would rank this as the single worst reason to hold a kid back. Being the smartest kid in the room can put your child at a significant DISadvantage. When a child gets used to being the smartest kid in the room, they can become more worried about maintaining that status than they are about actually learning or challenging themselves academically. Because the bar is artificially low for them, they also miss out on the chance to learn how to deal with challenge and failure while the stakes are still relatively low. You don't want law school or med school to be your child's first experience of NOT being the smartest kid in the room. Sooner or later, there will ALWAYS be someone smarter, and you don't do your child a favor by delaying that realization.
My mom refused skips for the reason you describe, and it only set me up for perfectionism, anxiety, risk aversion and fear of failure, which I then had to work through as an adult.
You might also underestimate your daughter. My son has been skipped two years and he's still at the head of his class academically in a school with a disproportionate number of gifted kids. If your daughter really needs the second skip, there's no reason to assume it will lower her grades. She might have to work harder to stay at the top, but that can be a good thing.
