I keep leaning to the .410 revolver
I'll wager you've never actually seen or held one... They're HUGE and not appropriate for conceal carry, especially for an average-size woman.
Anything over 9mm is also, generally speaking, not a good idea for a woman's first carry gun due to recoil.
I'll suggest one of the single-stack 9mm's such as Kahr CW9, S&W M&P Shield, Walther PPS, Ruger LC9, Bersa BP9cc, or, if heavier metal is desired, something along the lines of the Kahr K9.
Another often-suggested option for a newbie CC'er is a 5-shot .38 revolver.
Threads like this come around like clockwork. A dozen will say to get her to a well-stocked range and have her try out a bunch and find out what SHE likes.
It's good advice.