@Pearlylustre,
Dammit, Pearly, you made me tear.. from the pleasure of reading about that child and yours.
I can see the legitimacy of the question by toughcookie, as well as the questions re the "proud of" attitude; as I'm not all that versed in education issues, don't know current thoughts on all this, but others here do and will probably show up with opinions.
Me, I was an only child whose parents moved around, and I never had preschool, and only less than half a "semester" of kindergarten, and was admitted to first grade past present deadlines, given my birthday. Plus, I was small then. Grew up to be an almost 5' 6" woman, but was a squirt in first grade. Shy, beyond shy. So, I could have been held back, with reason. On the other hand, I remember that kindergarten, and I'm sure, sure, that I was much more engaged in a real first grade class. The shyness didn't just wipe away, but over the years I've become ms. tell you my opinion, which I think of as progress. Re me and my peers, age wise, not all that different; experience before first grade, I was a blank slate, more or less, except that my parents did read to me, etc. So, in my case, I'm not sorry I snuck into first grade past the deadline.