I heard from an old timer, if you can stick your finger in their ear without them making a fuss its time to ride them
I think you should start trying to get on her. Just make it for short periods of time. No longer than 10-15 minutes and no faster than a walk.
If I can get my fat old butt on my girls you can do it too. Sounds like you have gotten her ready for it. Wear a helmet, it does wonders for your courage level