I'm an only child, when my dad dies; does my stepmother get everything?Am I entitled to 50% in NY state?

My mom and dad never married. My dad has always been a part of my life. We are very close. My dad never married until I was 27. He married a woman he was living with for 23 years. They have now been married for 12 years. If my dad dies before she does, am I entitled to any of his property or money? I am an only child.My Dad resides un NY state.