Need insight

My ex (17F) and I (17F) went through a pretty nasty breakup about 6 months ago after being in a relationship for 3 months (and being friends for 6 months before we dated as well). We reconciled over the summer but still only talked as friends on occasion. Recently though (over the past week or so), we have been talking a few times a day almost every day. We both equally initiate conversations, there has been a bit of reminiscing on good times we had, and she even asked to hang out with some friends on the weekend (which I had to decline as I'm busy that day). We have not talked in depth about the breakup though. What does this mean? We've not talked this often since before we broke up.