Hi Jennifer, How about no bit at all? I think many of us have started horses with sidepulls, bitless bridles, even halters and lead ropes. I think something bitless would be my first choice. By the way, and excuse me if you've mentioned this already or someone else has asked it and you've answered, but have you had her teeth checked before bitting her? That's always good to do.
I'm restarting a little pony mare (approx. 4-5 years old) who was ridden much too young. She may or may not be part Icelandic. (Her temperament and the way she views the world says "yes", her build says no.) I have no idea what her training was previously, so I'm starting from scratch. I'm using a halter and long lines instead of a bridle. -- Renee M. in Michigan