Dear M S,
She is not too young. Puberty is only considered precocious if the signs are there before age 7 (yes, shocking). I remember that for me, I got pubic hair a year before getting underarm hair, but I don't know whether that is normal. My mom got her period at 10 (poor girl), I had just turned 12 when I started. I did get cramps every single morning for a whole year before starting my period. My mom told me I was probably fine, which helped me not panic.
My mom told me about periods when I turned 11, because I was due to travel on my own to another continent for 10 weeks to see a doctor (we lived in Africa and I needed to see specialist in Europe). She needed to know I'd know what to do when she was so far away.
I got pads in my room and I would pretend I had my period. I'd go to school with them on sometimes, then decided they were too thick for comfort and chuck them in the bin at break time. But it got me used to them, and meant I'd had practice putting them in and disposing of them long before I needed them. I plan on doing the same for my daughter.
My sisters are quite a bit youner than I am, and I remember they were nervous about getting their period. Talking to my mom wasn't enough, so they came to me for reinforcement. I put on 2 pairs of underwear, took them to the toilet, and showed them exactly what I did - including how to make sure you don't get your new pad to pick up germs from public toilets. I could just pull down one pair of underwear and put the pad in and be confident that I still was wearing a pair so I wasn't naked (bit of a prude, me). They are now in their late 20s and have told me that me showing them like that was the most reassuring thing, because they knew that they got 'full instructions'. Then they had a turn doing the same thing. It worked for them.
I knew a girl who wrapped her pad in tin foil so that if guys grabbed her backpack and tipped it out (you know what boys can be like), they would think it was sandwiches or a snack. It also meant she could walk to the toilet at breaktime with it in her hand if she didn't have a pocket, and none of the boys would know what it was.
Once I got my period, I made sure I ALWAYS had a pad with me. I had one tucked away in every coat and bag, so that whatever I grabbed in a rush in the morning, I would never be caught short if my period came earlier than expected that month. Last year I found a coat I used to wear when I was 16 ... it still had A. emergency pad in the inside pocket ;-)
Good luck! And don't worry, it may not happen for a long time. You could always ask your husband's sisters and mother how they were when they got their first period, just so you know if someone was very early.
A.