What club are you planning to shoot at? Clay shooters are a very generous bunch. I'd be willing to bet if you contacted the club they would put you in touch with an experienced member who would loan you a gun for your wife to try and give you both a nice introduction to the sport.
If she likes the game then go look at guns for your wife. She'll have at least some idea of what she liked
I am relatively new to skeet but I have been shooting for 35+ years,I am a member of a good club and last year I went out one night to check out the guys shooting skeet and tried a few guns and liked it so much that I went out and bought a cynergy.and I am sure that if someone there has a 20 or 28 they would let her give it a whirl I just wanted some input on what I should start her out on because she is super competitive so I know she will want to go out and practice before we go out and shoot with other people.