Hi Lizzie-
I waited about 3 months. It was quite apparent that there was something wrong (that I couldn’t hide) but waited to tell them exactly what until I understood it myself. My kids are all older, I have only one left in HS. If I had younger kids I don’t know how I would have handled it.
Anyone reading this post who have younger kids please offer your feedback, I know this question isn’t unique to Lizzie.