How To Ascertain That My Daughter Is Getting Periods?

hi my daughter who is 8 1/2 woke up on july 16 with a little blood in her panties. though out the day she complained of pain when urinating and told me as long as she held a peice of toilet paper down there it did not hurt and she could go better this last until about 9 pm the next night. it is possible that she could be getting her period. i start at around 10 1/2.