If I could give you a link to the private motorcycle site which is seemingly 40% military or ex military I would,(private site, invite only) They all choose Glock or Springfield, The majority Springfield, For conceal carry, the majority choose the XDM9. For me, before I joined the site, I chose the XD9 based on feel. I wanted to like the glock for reliability, but it just did not feel good in my hand.
Of course the 45 packs more punch, but not ideal for concealed carry, and not for a 70 year old woman, even if she is still well able.
Anyway, back to the O.P. Just like I did, and most other ppl do, and you said. You are just going to have to let her shoot a few and see what she likes, and feels right in her hand.
Sorry for the long post, but lastly, revolver vs. semi...I have never owned a revolver, so I can't speak to that. I can only say I have fired thousands of rounds through my XD9 at the range and it never has jammed once, And my buddy who I always go with has done the same through his Springfield 45, and I never saw him have a jam either.