2 month old sleep?

Are they still technically newborns? Me and my sister both had babies one month apart. So her baby is one month and she still sleeps like she’s fresh out of the womb. My baby just turned 2 months this month and she never sleeps like that lol. She takes lots of naps but I heard babies around this age still sleep a lot. My niece sleeps entirely all day long and she’s up maybe for a little while at a time and she goes right back to sleep. How should a 2 month old be sleeping right now? Not as far as a pattern but are they still suppose to be sleeping a ton?