She has faith in it. She likes it. Yes, I know that the 20 has far more versatility than the 28. But in guns of equal weight and design, the 20 seems to have noticeably more recoil than the 28. It is far more important to buy her a gun that she likes and enjoys shooting rather than saddle her with a gun that might have some slight technical advantage.
Perception is everything.
By the way, skip the 410. Don't even think of going there. Remember, you are getting a gun that SHE likes, not one that YOU secretly want. Make sure that she has a hand in selecting the gun. If you get her a gun that she doesn't like, she won't shoot it for long and it won't matter how long it lasts.