I'm glad to hear that, girls should be just as prepared as the guys.:smile:
I'm 5'4" about 125 lbs. and everything I carry is carried OWB.
What I carry could range fron a J-frame snubbie all the way up to a N-frame .44 Magnum, depending on my mood and where the day takes me.
The one issue I had to work around the most was my short torso, ribs almost connected to the hips, and she might have a similar problem being petite. I've learned that a lower rise pants is essential for me to be able to conceal anything I carry. If her pants ride at the waist and she is short-waisted she will end up with the gun riding too high with most off-the-shelf holsters.
A holster with 15-20 degrees of cant works best for me, try to find one with two slots to allow some adjustment of angle. I carry my Kimber Pro Crimson carry in a DeSantis speed scabbard and find it hides the best of all my carry guns, and I can hide it under an untucked tee shirt easily, bigger bulkier revolvers hide well under sweatshirts for me.
Shirt length can also play a factor, make sure the shirt is long enough to keep things covered. Teach her to bend her knees if she needs to reach something low and use her left hand to reach for things above, while holding her right arm at her side firmly enough to keep the cover shirt from riding up.
But do let her choose the gun she likes best. Take her to a fun shop/range that rents firearms and have her hold a few to see what feels good in her hand, then once she has narrowed things down to what holds and points well, rent and shoot them. Once she finds a gun she is comfortable with she will be more likely to carry it regularly.