>>543073529
Okay, assuming it's not completely random (even if it factors in time), it has something to do with traveling. I loaded this base file >>543073748 again and went to Central Area. I stood at the entrance near Blimpmon and hit x50 speed again and sat in place. I waited for about a minute (this time like 12 or so seconds less than the other two), switched it back to normal speed, then retuned to Cosmic Area and went back to the Theater entrance from there. She's older again.