I started at age 9. It's a few years early to start, but not terribly abnormal. Definitely get her in to see an OBGYN who is sensitive to dealing with young girls starting puberty at that age. It was a challenge for me to develop earlier than my peers, but my mom found a great OBGYN (after a really bad first one) who I had until he retired.
I also had other GYN issues as I developed and early onset menses can be a sign of certain problems, but it isn't always. Sometimes it's just early and that's it. An OBGYN will help in that area. I'd prepare her for the first trip to the OBGYN. I was terrified because I was 9 and being touched in those areas at that age is a shock.
Pads are a great start and reassuring her it's a normal lady thing as well can go a long way. I got mine in swim class of all things and I passed out. I was so embarrassed I didn't want anyone to know about it. My mom was unprepared for it at age 9 and hadn't talked to me about it beforehand, so I didn't know what it was at first. These days, I think kids are more in the know, but they're still kids and it's a tough thing to deal with at first.
Good luck!