I disagree, but here's why. I was 10 years old when I started my period, and I was 7 when I started getting pubic hair, and I was about 8 or 9 when I had to start shaving under my arms, and I'm 39 years old now. My mother was 9 when she started her period, so she knew she had to be ready to tell me all about this stuff when I was probably around 8 or 9, because nobody told her anything, and when she started her period at age 9 she thought she was dying. I knew how babies came into this world before I was 10 years old, and how it happened, and I wasn't grossed out by it.
Unfortunately, lot's of parents do not sit down with their children and explain these things to them, hence the question about using a tampon and still being a virgin. 10 years old is not too young, since most 10 year olds are just one year shy of middle school. If you aren't comfortable with your daughter being in that class, I completely understand, you should tell the school. We homeschool, so I do all the sex education. I taught my oldest daughter those things when she was 9, and my youngest is about to be 9. She already knows what a virgin is, and she knows what sexual intercourse is. She also knows that it is something done between married people and that God says it's ok as long as we are married.
I don't think your daughter will become interested in it prematurely if you tell her the truth. She needs to know that you can be open with her about this without getting embarrassed, or feeling uncomfortable, and that she can ask you any kind of question no matter how awkward it may be, because she may over hear a conversation about a sexual matter and not know what they're talking about and she may ask you. That happened to me when I was 10 years old when I was at our community pool and overheard some teenagers talking about oral sex.

I asked my mom what that was, and she didn't flinch or get drive into a ditch, since we were in the car when I asked her. She asked where I heard the term I used, and then proceeded to tell me what it was, and she didn't try to brush it off by saying we'll discuss it later. One thing I really admired about my mother growing up, was she was truthful with me when I asked about something like that, but she didn't use derogatory language, or anything, she simply told the truth according to how I could understand it, and that was that. If you make too big a deal out of it, and side step the issue, she's going to find somebody else to ask, wouldn't you rather it be you.