My wife had about every used girls bike. A 500 ascot, too tall, 250 Rebel, too cruiserish, GS300L, one of the best except for the drum front brake. Knowing what i know now, I could have fixed that (by brake arcing), Our 1988 650HawkGT was hers to begin with bought new. She liked the sportiness and power, but it was still too tall. her most miles she put on a 600 Eliminator. Now that was a piece, 600 Ninja motor tuned for torque and she like to use it. Put about 25000 on that. Drive shaft, long intervals between valve adjustments, a little cold blooded, if it been sitting I had to get it started for her. Most recent and most civilized was a 400 Burgman, a Max Scooter. Don't let the "scooter" fool you. THese are fast comfortable, we went on 3 600 mile overnights, the massive trunk let her take her full purse. At a restaurant she could ditch her helmet, brush out her hair and take her purse in. No shifting, way low maintenance (good for me) enclosed belt drive, fuel injected, starts first time every time. we went on the Interestate quite a bit, it has as much rider protection from wind and rain as my FJR.
Just some thoughts. But seat height is always the problem, don't know why the Japs don't address in a big bike that's not a cruiser. Takes forever to turn those around. On trips out in the wilderness, that was Linda's biggest complaint about the Eliminator. If she had to turn in a tight space, I often had to help, like on a narrow 2 lane road or in a small parking lot. THe Burgman is still kinda high. THe Eliminator was about 29", pretty low.
We've met many couples travelling where the female was on a 250 Eliminator. A little short on range and carrying capacity, but a GREAT bike. I think it vibrates a bit at speed.
You may find if your going to ride together that if she gets in a tough spot and needs some power the 125 won't have it. But its a great bike too. THe entire Eliminator line up was under appreciated.