So long ago, but I remember it like it was yesterday. For me, it was pretty much a day. I remember I had the WORST cramps ever (which I still get!) and was supposed to be running errands with my dad. I couldn't get out of the car. I remember thinking, well maybe this is what my period is. Went to the bathroom and nothing. Later that night, I wipes and saw a bit of pinkish. Told my mom, wore a pad, and by the next day, there she was. I didn't get it again for about 3 months tho.
I remember the day too, 36 years ago. It was the night before the first day at a new school...I was nervous, and I had been in a foreign country for the last five years, and felt like a real dork. That night I got the weirdest backache, and my mom told it me it was probably nerves...
Well, about an hour into the first day, it started. I was wearing white pants, and my mother never had told me anything. I went to the girls room and saw blood, I was shocked and too embarrassed to ask anyone. I made it all the way through the whole day with those cheap wax paper-like bathroom sheets, rode my bike home 2 1/2 miles and rushed into the bathroom.
My mom had a kit under the sink with the instructions, and to the day we have never spoken of periods at all.
Thank goodness things have changed, and new we can talk about this. You will probably have some pretty clear signs before it happens...Good luck!