<p>The practice of holding kids back from kindergarten for a year is called “redshirting”, and it’s done for may reasons (not just sports achievement), particularly in the case of boys, who tend to mature more slowly than girls emotionally, socially and intellectually and often don’t really belong in the same classroom with those girls. It’s quite common these days, as we’ve learned over the years that chronological age shouldn’t be the sole measure of school readiness. Bottom line, OP’s age won’t raise any eyebrows at all.</p>