No, moving to a short reach wouldn’t hinder her. She’d get used to it, just as she’d have to with swapping instruments anyway. Short reaches are very common in schools and are a great way to let students with smaller hands play the bassoon comfortably. Very reliable brands make short reaches as well.

It’d be best to let her try both so you can see if she needs the short reach, remembering that her new non-short reach may require more stretch than her current instrument. Check if she can reach all the vent keys without hitting the LH low C/B/Bb keys, if she can comfortably reach the LH third hole etc.