I know i ask alot of questions but please help me?

as u may know i am 16 and my bf is 17 well any way on to the questions.1.why did my bf get hard while watching the book of pooh while babysitting his 3 year old sis?and no it wasnt the boy the animals or his sis so what was it.2.how should i tell my bf we cant have since i have my period cuz he is so horny ? no it is not my first period i got that at eleven 3.i think my 13 year old sis stole my pack of marbrol reds what do i do about that ? 4.can some one get horny by reading the harry potter books ? 5. is it wrong for a 16 and 17 year old to be drinking beer that my older bro who is 24 bought for us ? and i have other questions that i need help with but wont all fit so will u im me at luveroffrankiero to help me .