Snowsuit size ladies helpppp πŸ˜‚πŸ˜‚πŸ˜‚πŸ˜‚

Angel

Ladies I need your help, my babyboy was born out 27th 6plds 10punces he is still in newborn size and also fits a few 0-3months the thing is he's long born 21inches so he appears bigger but weight wise still tiny.πŸ’™πŸ’™πŸ’™πŸ’™πŸ’™πŸ’™I'm alil lost on a size to buy him for his snowsuit, we live in NY and winters here can be veryyyy cold. Buttttt if I buy him 0-3months by February he will be 4months and idk if by then it will fit him, what would you ladies buy 0-3or 3-6? My fiancΓ© says 0-3 but I'm just worried were thinking toooo much of the now and by the coldest month of the year 0-3length wise won't fit him. But then I think is 3-6 months toooo big????? Or do I buy both as my fiancΓ© keeps telling me if I can't decide lets just do that . I'm a ftm so plz help. Lol.