14 year old needs help from women! please help!!! any docs will be HIGHLY appreciated!?

heres the position i am in right now. i have growth hormone deficiency adn adrenal insufficiency. my endocrinologist told me to begin taking provera birth control to get my first period and i have been anxious for this for years. i have an appt with him on the 20th of july. i will begin taking the pill on the 20th of june. my mom and i just figured out what date i should take it after i flipped out at my dad and i think that gave her that idea because i seem to have been moody and emotional lately. anyway i have a 3 day camp to go to with my dog on the 27th-29th. i think that my doc said it will untill the end of the term of pills or a bit after it to make it come. it is like 12 days i think. also i have a camp to go to in july from 24th-29th. i really dont want to get my first period at dog camp adn i dont care if it will come at camp just not untill the last few days. after typing all of this, i cant remember what my question was honestly. but do you think this will work out and any advice? thank you! :)