First time mom trying to get my crap together before the big arrival. Looking at car seats and wondering are the stage 2 (5-40 lbs rear facing) safe for newborns? I see most people going with the stage 1's, is this more for convenience? My sister bought one for my nephew and he was out of it in 2 months....just wondering are the stage 1's necessary? I understand they are convenient, I just want to know if our baby will be safe in a stage 2 as a newborn. Thanks ahead for any info!!