I was recently thrown into this and it is scary as a parent or carer to know how important it is to get this stuff right for our girls!
I found that the age appropriate books about changing bodies really helped with topic starters and let our little person feel open with asking questions.
I remember that this was not a conversation topic which was openly and freely discussed when I was younger so I guess I want it to be not taboo in our house. I think the body language and tones you use when talking really can have an impact! I've tried to make sure I look and sound comfortable with talking about all things puberty even when inside I'm uncomfortable as hell! Like the time when our 11 year old asked of she could have one, referring to the condoms in the dispenser in the ladies public toilets and then asking why not, and what they were for! Lol!
I think your doing all the "right" things in being open and honest with your DD.