If you are worried about noise,Jim Gaska has a shroud extension that is very nicely made, works well, SO nicely made I'm surprised at the reasonable price ($35). Most of us find the PRod decently quiet up to about 13 foot pounds, but once the power is pushed past that, the small volume of the shroud is kind of over whelmed.
A bit more pricey ($125 but still a good deal) are drop in LW barrels (and they really are drop in). Would NOT buy one unless your PRod barrel proves to be one of the picky ones; some shoot well and others are problem children.
Stock is of usable length for an adult...might need to figure a way of shortening it for a small person. Does have a very low cheek, which does not line up well with scopes. Prefer a cheek riser...can be simple of complicated, just want my face to feel some support when away from the bench. Mine is pretty simple:
shaped wooden dowel
two lengths of Al rod
SHOT counts: Speed always costs air. Faster you go, the more air you use. P Rod has a small volume and is not destined to give a long shot count with a low velocity spread. While I have run my PRod to 18-20 foot pounds, the shot cout inside of 20fps was pretty low (like your guess...12 to 14 shots).
Unlike most, decided to set mine for 12 foot pounds. Get a pretty decent shot count that way,
.22 Disco can do much better at that same energy level (18-20) once set up right. More like +30 shots.
One way to look at shot counts is to run this efficiency calculator backwards...can play with the numbers and see just how many shots you could expect at various efficiencies. Realize that a bar-cc/fpe efficency of 10-11 is quite good, so consider that about as good as you could do.