i agree w/ the revolver suggestion. our daughter insists on 22s. she has shot my 32 mag ultralite before & does okay. that's actually what i carry most of the time simply bc i love my gun.
like i tell her, shot placement is key, but i would highly recommend the revolver. all you have to do w/ those is point & click.
& nothing substitutes for PRACTICE. caliber means nothing if you cannot hit the broadside of a barn!