Is Your Child an Introvert?

One of my children is an introvert. And my spouse is an extrovert. I really wanted to just see, it was so different from the way I moved through the world. It was very clear that I didn't really know how to be as good of a parent as I could be or my other child. They were still pretty small. But when did you first realize that this kid was sort of reacting differently? Like did you have the other kid for comparison already?