She doesn’t necessarily need a short scale. There are plenty of crazy YouTube videos of kiddos tearing it up on regular scale basses. But She won’t really know what’s most comfortable for her until she plays one for a while, then goes out and tries the other.
In the era of normal business hours, I’d say go out and hold Basses. If she’s played guitar and cello, she’ll be able to make some noise. Hold the neck, see how it feels in her hand. Put it on a strap and see how it balances. if you can wait til this is possible, that’s ideal.
but if you want to get this during stay at home orders, you may have to make an educated guess. Do you have the funds to buy 2 Basses, try at home, and return one? One short, one regular? Most major online retailers have generous return policies.
Most of the basses recommended here are fine quality for a beginner. I think the Yamaha and Ibanez have exceptional quality control at this price point, but the others would be great as well.
For amps, a Rumble 25 or Ampeg BA108 would be my pick.
Finally- ask her! If she helps pick a bass she likes, even if it’s just for looks, she’ll be more likely to play it. Instead of this ugly thing her dad picked out
and watch videos of female bass players for inspiration! Off the top of my head:
Esperanza Spaulding
Haim
Tal Wilkenfield
Ida Nielsen
good luck on your quest!