Grass is always greener. You don't know the counterfactual and you would have likely been disappointed in your parents had they sent you to college early as well.
I do think listening to any of the professional educators who unanimously and repeatedly told my parents it would have been better to accelerate my path through school would have been a good idea.
Do you have any experience with folks who went to secondary education early? Because I was miserable in high school bored out of my mind and left 1 year only and my only regret was not leaving even earlier like some of my peers did. Speaking platitudes like "the grass is always greener" may make you feel better but it doesn't line up with 25% of the profiles of students I've seen go to secondary education early (and I know a lot of them).
I did hang out with a 15-year-old at college and he seemed to have a relatively normal college experience.
Personally I had a 2 year gap between high school and university, so I went from being one of the youngest in my year to one of the oldest,which was kinda nice. Plus the time away taught me some self reliance so college was pretty easy to adjust to.
So yes, in the modal case (advancing with the cohort) a student entering college will start at 17 years old if their birthday is late in the year.