ya know, your situation is similar to my wife. when i first took her shooting, i had her shot my buckmark 22lr. she was apprehensive about it, but she shot it. she felt comfortable shooting a 22lr. after that, i had her shoot the 10/22 to get a feel for it. she liked it. then i had her try my beretta 92. she didn't want to try it, but said you shoot it first. i put 1 round in the magazine and took a shot. afterwards, i put 1 round in the magazine and told her to shoot it. i kept reminding her that there is 1 round. she felt comfortable shooting 1 round because there couldn't be a 2nd shoot. after she shot the 9mm, i asked her how it was. she said that it was more powerful than the 22lr. i put in 3 rounds of 9mm in the beretta. she fired off all 3 rounds. i moved her up to 45acp. i told her that the recoil would be harder than the 9mm. she fired 1 shot and didn't like the recoil. the final gun she shot was a 357. she really didn't want to shoot that because the ammo was larger than the 45. still, i had her shoot 1 round of it. she actually like it because the recoil wasn't as harsh was the 45.
basically, my method was to make her comfortable by only letting her shoot 1 round at a time. if she liked it, then i would let her shoot couple more round of the same caliber. that made her feel comfortable because she couldn't fire off an accidental round. hope that helps dude.
I am offically a gun nut!!!!!