Newcomer Question!

Okay so my cycles have always been crazy and unpredictable and I've tried a bunch of apps to try to predict when AF will come, this is the first that has gotten it almost exactly when it came, but mine are usually pretty heavy for the entire time, I don't really get light days...this time I got a "24 flu" and then that next day I started, but this is the lightest period I've had since I first ever got AF 8 years ago lol I could be paranoid since technically the app said I was going to start that day, but just seems weird to me and wondering if anyone else has ever had it happen? Thanks in advance!