Sorry we didn't see this earlier...
In your prior thread, indigo gave you an excellent curated list of information on acceleration. If you haven't yet done so, I would encourage you to familiarize yourself with the research on grade acceleration, keeping in mind that this is group data, and every child is an individual, with unique needs and strengths.
But to highlight some of the relevant findings that decades of research have found as generalizations:
1. Group data consistently indicates that long-term outcomes are more positive (academically, socially-emotionally, self-advocacy) for HG+ children who are grade accelerated than for IQ matched peers who are not.
2. The disadvantages of grade acceleration are most likely to show up in petite, socially-reserved boys.
I cannot emphasize enough that both of these reflect group data, and that what is best for your specific child may be quite different than what has been net most beneficial for someone else's child. IOW, the group data says acceleration is generally more positive than not for HG+ children, but that when there are social impacts, it is most likely to fall on boys of small stature.
Critical protective factors include the attitude of the family (e.g., instilling values and assurance in the child that prioritize internal character over external appearance), and the attitude of the adults in the receiving classroom (including administrators, the lead teacher, and supporting teachers). If all of the adults involved are supportive, and communicate matter-of-factly both to the student himself and to his classmates that this is just what this particular student needs to learn and grow, just as teachers and parents try to provide what each of his classmates need to learn and grow, that can go a long ways toward offsetting the potential social costs.
Another key finding is that HG+ children on the average tend to gravitate toward older children anyway, and (again on the average) tend to be more advanced in social-emotional development. Not to belabor the point, but this is of course highly individual to the child, and even the moment in the child's life and development.
You know your child best, so these would be questions for you to ponder yourself first. If, in your assessment, you believe your child could adapt socially and organizationally to the peer and self-monitoring demands of second grade without having experienced first grade, then the conversation with his teacher and principal would need to include considering how he has interacted with peers this year. If there are older children in his K class, did he play and work well with them? How are his self-management skills at this point...behaviorally, and with independent task completion (within the developmental expectations of K)?
Additionally, in this particular school year, is your district planning on distance learning, hybrid, or fully in-person? I suspect that predominantly distance learning will obviate any social-emotional gaps that might otherwise occur.
Finally, consider whether instructional underplacement (in grade 1) may actually exacerbate any social-emotional immaturity, as it does for a not insignificant fraction of HG+ students. There will almost always be mismatches somewhere in development for HG+ children, who tend to be highly asynchronous. It's just a question of which areas of match are most critical to his overall growth and happiness as a whole human being at this moment.
And, FWIW, someone is always the youngest in class. The data on redshirting age-eligible students to avoid being the youngest is pretty uniformly neutral to negative on long-term outcomes (i.e., high school dropout rates, self-esteem).
Full disclosure, in case you can't tell, I have a personal bias in favor of acceleration (others on this board feel otherwise, for valid reasons). Whatever you end up choosing for your child, know that someone will likely criticize your decision. Listen respectfully, of course, in case they have valid points, but don't let them override your confidence as a parent. No one knows and cares about your child as well as you do, and you are making the best decision you can for your particular child. Also, remember that if you don't skip this year, it doesn't eliminate the option in future years (or even in the middle of this coming year), and if you do skip and it doesn't work out, nothing prevents you from undoing the skip. The same comment above regarding how to protect him from any negative impacts of a skip applies to changing course in the future as well.
