Was this a throw or a fall?

Definitely a fall. You kicked her too hard and she did what she thought she was supposed to do. If she didn't turn suddenly, rear, or buck with the express purpose of getting you off then you did not get thrown. All horses would spook if there were screaming kids. Explain to your dad the fight or flight reflex horses have and that us just jumping a bit at a loud noise is equal to them running away or shying.