@sum1005 I’ll answer by saying that both things can be true. Your daughter’s score may be reflective of a lack of preparation, and, your daughter’s score my be reflective of the quality of your current public middle school. For me it’d boil down to whether some focused work on the former would make up for the latter.
I concur BTW with the advice above that 10-15 minutes of prep/day, a few days/week, for a couple of months prior to the test may be plenty. I’d start with the official book and go from there. Have her take the test again to see what kind of traction a little prep gets her. If not enough, maybe ramp the prep to include more time or even a tutor if you can swing it.
That said, you may find that the prep isn’t enough and face the decision to switch schools sooner rather than later if possible. Here’s another wrinkle: the additional prep may get her the score you/she wants, BUT! you may still want to move her prior to high school into an independent MS with greater academic rigor. If there really are issues with your PS district’s quality, she’ll be better prepared academically for a top BS elsewhere. Again, all assuming you can swing it.
Good luck regardless. Take it slow, and remember you are already way ahead of the game by having her take the test in 6th grade…