If you report to the authorities, don't just tell them that you suspect she is pedophile. Leave it upon them to decide whether she is. You can do it by telling all the relevant details: copy-paste the relevant parts from your messenger history, or if you don't have one, try to reproduce them as accurately as possible. This way you don't have to think afterwards whether you caused harm to someone who was just fooling.
Even if she invited kids to her place, she might have been joking, it's judgment call, but if the whole thing creeped you out, it's a sign that there's something to be worried about.