Maybe it will age a bit later. Because it happened to me once, my tamagotchi aged while it was sleeping and all. Once (when I first got my tamagotchi), I had an obotchi. It was suppose to turn 2 but it didn't. I called up my friend and she said it was normal. Just leave it alone and it will age by itslef. Another reason could be just as dr.tam said. But I decided to reset my tama in the end and now it is only on the 2nd Gen .