First go to the system setting on your 3DS and set the clock to the same day as you adopted the villager (remember the day begins at 6 am! So if you adopted her yesterday, it has to be somewhere around 6 am on saturday and 5:59 on sunday). Then, load you mayor and pay attention to the day and time Isabelle says. If it's within that frame, it's all right to load your mayor, there will be no plot. So you can set the patterns, save and quit. Then go to system settings, change to the right date and time and plot reset as usual. I've done this in the past and it worked.