hi,
i'm so happy to hear that your reunion with your bmother is going well.
about your concerns of what to call her...i think you should just speak with her about it. let her know you don't want to hurt your amom, and that in front of her you will use her first name. give her a chance to tell you how she feels, but ask her to respect your request.
i'm a bmom, and though my bdaughter does not call me mom, if she did i would certainly understand it if she were in your position and did not want to in front of her parents.
is your amother supportive of you reuniting with your bmother? it must be a little hard for her if you two aren't so close right now. i know it is exciting to reconnect with your bmother, but remember, there is no reason you can't love them
both and have a seperate mother/daughter relationship with each of them.
for all of your sakes, i hope it doesn't turn into a who-is-my real/favorite mom contest, because imo, we all have room in our hearts to love more than one person dearly!!! it sounds like they
both love and want the best for you, each in their own way...
good luck