I do have a wonderful website!!!! And, I have heard my book is even better.....old school paper!
I understand your fear about announcing your PSA's commitment, thus removing her from consideration with other colleges. My worry would not be that a college coach would pull the offer, but in today's collegiate environment, my worry would be that the coach would be fired. It can be a non-sensical college athletics world with coaches getting fired with good records, bad coaches keeping their jobs without rhyme or reason, etc., etc.
As we are already in April, the firing season is 99% done and the hiring season (which could result in a college coach leaving one school for another) is 80% done. This inexact mathematics equation results in your PSA being 97.6% safe in having her scholarship before and after she signs for this year!
Long story short, you are good to announce your verbal commitment and signing day is not too far away by now. It is better to let the other collegiate programs recruiting your PSA know of the commitment, so they can move onto the next athlete on their recruiting database (and it is also better for this next athlete because maybe this VolleyFamily really, really wants to attend your back up college?).
Congratulations on your PSA's commitment, now relax and enjoy the remainder of club volleyball and being a high school athlete because college volleyball is a train wreck!!!! Just kidding.....kinda.....