You figure grape juice and wine aren't too different and that what goes better with a finely aged wine than a finely aged woman.
So with your powers you make it so when anyone drinks grape juice from this store the juice will turn into wine well the person gets the body and wardrobe of a sexy, classy, mature woman with a love for wine. anyone made older by the change will stop aging until they would've reach their new current age and no one will have any issue with the changes.
Soon after your done you see a mother grabbing some juice for her young son. Little does she know by the end of the day her "son" will be older and sexier than her.