Oleg,
With all due respect, you aren't listening to your Mom. Your Mom,like my wife, has found her comfort level with the Buckmark. Sure, I would feel worlds better if my wife would learn to use my centerfire's, but she is by far more comfortable with her Buckmark Micro. My advice to her was just keep pulling till it's empty, then put in a new mag. High stress situation, and a lack of confidence is a disaster in the making. A Buckmark Micro w/10 rounds of whatever ammo it likes best is a far better choice than cowering in the corner or making scary faces to ward of an attack. Get her a Micro, lots of range time, and let the bigger stuff come in it's own time, if at all. I know you may feel better if she was better equiped, but really, what you feel is 100% a non factor if there comes a time she needs it. It's how she feels that counts.
Just MHO, based on the number of years my wife and I have shot together. It was only last fall that my wife expressed interest in trying my Hi-Power. This after 22 years of shooting together.