No doubt about it, tall, with long fingers, long arms and large hands. They get closer to the batter, have more levers, and spin the ball easier.
Big colleges rarely look at a pitcher under 5'9''.
Colleges make shorter pitchers into other types of players (Lauren Gibson, for example)
That does not mean a shorter pitcher can't do it. Jacksonville State, I think, made news in Regionals a few years ago with a 5'1" or 2' pitcher, IIRC.
College coaches take pitchers that can throw 60+ and can pitch regardless of height. That said, height, long arms, fingers, etc may help girls throw harder thus givine a perception that coaches only look at taller girls if the roster is full of taller girls who throw hard.