Buckling up is a habit for me.
I'm thankful to hear about your daughter. Be advised, however, that many people are killed each year by injuries from seatbelts and in some of those cases the passengers and drivers would have survived without them. Furthermore, I do have a friend from college (extremely athletic) who was able to jump out of her set in a sideways collision before the car came through the side of her vehicle. If she had been trapped there she would have died.
STATISTICALLY, you are more likely to survive with your seatbelt on. But it is not better in all cases. There are cases where wearing the seatbelt will kill you. The government has no business legislating the demise of a minority to achieve the protection of the majority.
So go ahead and preach, but don't cross the line into statist fanaticism.