Answer: Normal is different for each newborn baby, and sleeping patterns are no different.
On average, newborns spend nearly 17 hours a day sleeping. This does not mean that your newborn is abnormal for sleeping only 12 hours, and it is possible that the amount of sleep your baby needs changes in the near future.
The average is exactly that – just an average. Many babies sleep more or less than this. There is no need to worry that your baby is not sleeping enough if this is the case. The most important thing is that your baby seems alert and healthy during those hours spent awake.