In New York, for first degree the victim must be a cop, prison guard, first responder, judge or witness to a crime,
or
the murderer must be a burglar, contract killer, inmate for life, or terrorist.
There's a few other possibilities, but if you murder someone "normal" and it's your first time, generally it's second degree in New York.
https://www.nysenate.gov/legislation/laws/PEN/125.27

First degree has a minimum sentence of 20 years and can get you sentenced to life without parole.
Second degree has a minimum sentence of 15 years and you have a chance for parole afterwards.