When you say "Shimano 105s", I think you mean the pedals using Shimano's SPD-SL clips, right?
You might want to consider trying Shimano SPD pedals; my wife is trying to go clipless as well, and these are the same pedals I used when I first started. While there are road-specific designs, I found Shimano's trail versions very easy to use and learn on. The first pedals I had included a platform surrounding the clips, so you could still use them like a regular flat pedal. The models I used were also dual-entry, meaning you didn't have to think about which side of the pedal you were trying to clip into.
An added bonus is the shoes for the SPDs usually have a recess the cleats fit into, making it easier to walk in them.
Here are some examples:
This is the one I started with, with the surround (Shimano PD M424):
This is a similar pedal without the surround (Shimano PD M540):
There are numerous other versions of the SPD pedals, so you have a lot of choices. Good luck!