I don't do any U-Trip, so I could be completely wrong here. This sounds like: Ball in the strike zone, batter hit by pitch = dead ball strike.
However, to make conversation, let's nitpick OP's situation: "Elbows parallel to the ground over the plate". (paraphrasing) When I look in the mirror, that means my elbows are above my armpits. This is a ball in all codes I work (except 8U...he he he sigh.
). Did she drop her elbows to swing? If so, the elbows are inside the book-defined zone if this isn't a college game. I can't imagine the motion required to extend the elbows farther into the zone on the swing, but then again, I have seen some real ugly swings. This is where we make the big bucks: was the elbow in the zone or not.
Luckily the rule is clear in most codes. (1) Either the ball was or was not in the strike zone. (2) Either the ball was or was not entirely within the batters box. (3) Either the batter did or did not attempt to avoid, in the judgment of the umpire. As mentioned before, a starting a check swing and then getting hit may or may not be an attempt to avoid. HTBT. Apply the applicable rule based on these three yes/no questions.