a day as someone else

"wait, you know that i was a boy?"
"of course, i was at the library when you changed"
your confused now, why was your sister at the library?
"what were you doing at the library?" you ask after awhile.
"you never pay attention, do you? mom and dad left for vacation today and said that i had to go with you to the library today. when you picked up that book, you started to get shorter and you were glowing a pinkish color so i followed you and watched you change. after you fainted i asked this cute boy to give us a ride back to the house."
ok....it makes a little sense now, so sense your sister saw you transform, she knows what happened...
"oh and by the way, that books not blank," your sister says, "i was reading through it. it said that only true girls can read the book. thats why you changed. it also said that if you do change, the only way to change back is to live as a girl for a month, using the book as a diary each day. otherwise yourstuck forever."
great, you think to yourself, if i dont start to act like a girl i'm gonna have to stay one forever.
"so...umm...i'm stuck this way for a month?" you ask.
"yup!,"your sister says excitedly, "you get to be my big sister fo a month! come on, you've got lots to learn before we go back to school on monday!"