Counselling apointment coming up, should I tell my dad I'm ftm ed?

K, so I have a counselling apointment coming up and it's gonna be my mom, my dad, my stepmom, and I . My dad and I are a bit distant, but were getting closer and my stepmom, I haven't talked to in over a year and is the reason why my dad and I are so distant, and we don't get along 75% of the time, because she often says things that lower my self esteem... My mom knows I'm trans, my counsellor does not, my dad and stepmom also do not know, but I know they have a male gay friend....my mom thinks my dad will be okay with it, but she doesn't think my stepmom will be.......and I'm going to counselling for family issues regarding my stepmother.............so my questions is......should I tell them at counselling, or waittil another time????.....and is it possiblethat my counseller can set up an apintment with a gender therapist???