There are a lot of important considerations when deciding whether to skip a grade or not, but this is the first time I’ve heard a “big reason” is wanting their child to be 21 or older for a larger portion of time during college.
If that’s a reference to drinking alcohol, being under 21 generally doesn’t stop students from drinking in college. At the college I attended, if anything it was the opposite. A much larger portion of students drank during freshman year when the overwhelming majority were under 21 than any other time during college. However, for a large portion of students, including myself, a quality college experience had little to do with drinking or being 21.
When deciding on a child skipping a grade, I also wouldn’t assume that he/she is going to attend college for exactly 4 years, then leave. Many students take 5-6 years to complete a bachelor’s which can relate to doing a co-op, studying overseas, pursuing outside projects/situations, taking time off to work, athletic redshirt, gap year(s)…, . Many students attend grad/professional school or have complex degree plans than a traditional bachelor’s. Many students also do not attend/complete 4-year colleges and/or do not attend college at all. The majority of students do not follow a traditional path of exactly 4 years of college, then leave.
If it were me, I’d focus more on things like the academic reasons for skipping or not skipping. For example, I was bored out of my mind in many classes during grade school, which contributed to subpar performance, including weak grades. With increasingly little challenge, there was increasingly little effort and interest, which could have led down an increasingly poor path. Fortunately, some teachers recognized this and gave me the opportunity to do things like independently study at my own pace or be a half-time student at a nearby university while in high school. I believe skipping a grade would have benefited me overall, had I been given the opportunity.
I completed my first master’s at age 21 as part of a double co-term program (simultaneously pursue BS+ MS + MS), which put me ahead of the traditional age schedule. I don’t recall ever feeling disadvantaged because of being younger than most students within my academic year during college. Instead my classes generally had students from a good variety of ages, and I don’t recall any students asking my age. In general, nobody within the college cared if I was 20 vs 21, vs 22. Similarly my friends were not limited to being a specific age or academic year. Yes, there is a theoretical scenario where your close friends are all within the same academic year and you have to tell them that you can’t go off campus to a bar or other place that checks ID with them because you are not over 21 (and want to follow the age rule). That doesn’t sound like a disaster to me or a good reason to not want your child to skip a grade.