Hitters have trouble because they can never predict what she will throw. Chelsea is not afraid to come in one batters and throw her off-speed pitches at any time in a count. The transition to college was not without its challenges, the first of which was the change in distance to the plate. You are at 43 feet as opposed to 40 feet. Moving back three feet is a distinct disadvantage.
Pitches break differently.
They break too early and out of the strike zone. You have to adjust without stopping the break. That leads to other difficulties that had to be handled. You get hit freshman year. There is no way around it.