My issue - here, and in general - is using just the right amount of force. Specifically, I wonder if I'm using too little force - to the point where she feels insulted. I don't want to use too much force, either, and seem inconsiderate.
Has she given you any indication that she thinks you're using too little force, or patronizing her in any way? If not, then you really DON'T have a problem
Usually uke will indicate if you can crank it up, or if you need to crank it down. As you advance you'll also feel their arm tightening up, their centre being taken, and have an appreciation for their ability in ukemi, which can help you gauge your throw.
It's really good that you are open to developing sensitivity to your training partners, as there are too many who just see other people as a rag doll or a throw toy!