Ooo ooo ooo, I don't know much about guns, but I can help here a bit (I think).
I LOVE my ML for deer. I love it way more than my shotgun for deer because yes, that shotgun kicks a lot more. That being said, I was started off with a youth model Remington 870 20 gauge. Yeah, shooting slugs out of it is a bit of a b***h, but doable (I am very slight framed). But the great part of that shotgun is that I have used it for turkey (it still is my go to turkey gun), rabbit, squirrel and dove. With a shotgun barrel and a slug barrel, it is the ultimate do-it-all gun. OK, not do-it-all, but certainly it is a versatile gun. If you get a ML, then it is all about shooting deer. Of course, you can get a ML pretty cheap so you could get her 2 guns. hehehehehe!