For myself, we our bred our pet dogs (whom lived inside with us), so I had some demonstrative evidence about how it worked. We even put a makeshift cloth nappy on the female when she was in season so she wouldn't leave blood all over the house.
Sex ed in primary school was about your family tree, and that babies are lots of work (changing, feeding, entertaining, bathing, etc). In high school it was all about condoms and STDs.
It was the 80s and the high school library had heaps of pamphlets on STDs, especially AIDs. I read them all. Next I went to the encyclopedia and looked up intercourse.
At 13yo, I rode home from school and found the seat of my bike red. I knew I had obviously gotten my period but didn't really know anything beyond that. No-one was home and I went to the bathroom and cleaned up. Blood was not coming out at that point, so it was obvious to me that it was all over. I was surprised because I thought it was supposed to last longer. I also thought I had best tell my mother so went searching for her at likely places, such as the local shopping centre.
By the time she finally arrived home with my uncle in the early evening, I was distraught because I had spent all afternoon looking for her. I exclaimed that she was finally home and asked where she had been all day. My uncle ridiculed me saying that I wasn't a baby and didn't need my mother around all the time.
Finally I managed to get a quiet word with my mother and told her that the reason I was looking for her was to tell her that I had my first period. Her response was to hand me a box of tampons and tell me to go into her room to put them in. I tried to explain that it had finished, to which she told me I was wrong and it would last days - and sent me off into her room.
I read the instructions and then attempted to insert one, but wasn't able to. About half an hour later my mother came in to check on me and I was in tears because I couldn't get the thing in. She pulled out a partially used tube of thrush cream and said to use that as a lubricant. I did so and it worked. (I continued to use the thrush cream to insert tampons for about a year, until the tube ran out - then discovered that I didn't need it anymore.)
My mother also impressed upon me the importance of not telling anyone (teachers, classmates, administration, guidance officer, no one) at school, because I would get teased about it.
The next day I went to the school library and looked up menstruation in the encyclopedia.
When I was 14yo, after I was sexually active, one day I arrived home from school and my mother told me she had gotten some books out of the library for me and put them in my room - and told me where she was off to for the rest of the day as she walked out the door.
I went into my room and found "Where did I come from?" and "What is happening to me?" sitting there. I gathered she had left so that she wouldn't be around to answer any awkward questions. I read them and laughed that she thought I didn't know this stuff by now.
In year ten, our science teacher spent a lesson talking about the human body. She covered many topics, including the use of the pill to control painful periods. And also offered anyone who had a question they weren't comfortable asking in front of the whole class to stay behind and ask her privately afterwards. A boy stayed behind and asked about why he would get hard-ons at inappropriate times. The teachers answer was enough to clue me in about the fact that the male appendage gets erect. Before this I was completely unaware of this fact. I knew all about wet dreams but didn't know that a penis had an erect and a flacid state.
Okay, that pretty much outlines my education in the area. Your turn.