^^^ wyeaster beat me to it. Lots of armchair tough guys posting up.
I remember taking headers as a kid (played into high school) that at times did not feel good at all. I'm generally in support of limiting them until a certain age. Not to mention the fact that kids generally just aren't very good at them until high school anyway. Insufficient neck strength to change the ball's trajectory, etc. Pre-high school they should be working on effective chest traps more than anything else.