Why am I so paranoid about sex?

Mmkay I'm 13. I want to have sex really bad but I still don't have a boyfriend and blah blah blah. I KNOW how to not have sex with a guy that I JUST met. I like to go out with a guy for awhile before I do anything like sex. But when I do have a boyfriend for like a year I would like to have sex. But I am always freaking out about getting pregnant!...

How can I give my sister a good sex education?

I am 17, and I have a 15 year old sister who is Autistic. I also come from an EXTREMELY Catholic family. I never got a sex talk - I straight-up asked my dad what sex meant when I was 9 or 10, and he gave me some very unhelpful answer about a gift that God intended to be shared between a man and a woman in marriage....