Because if you are 18 or over, you do NOT need a family member or lawyer to appear with you.
That said, here's the charge:
NY Penal Law §221.10 said:
Criminal possession of marihuana in the fifth degree.
A person is guilty of criminal possession of marihuana in the fifth
degree when he knowingly and unlawfully possesses:
1. marihuana in a public place, as defined in section 240.00 of this
chapter, and such marihuana is burning or open to public view; or
2. one or more preparations, compounds, mixtures or substances
containing marihuana and the preparations, compounds, mixtures or
substances are of an aggregate weight of more than twenty-five grams.
Criminal possession of marihuana in the fifth degree is a class B
misdemeanor.
Was the joint lit when they stopped you? Were you a dick to the cops? Normally, for such a small amount, you would get charged with 221.05, which is like a parking ticket. In comparison, you were charged with a misdemeanor.
In any event, you do not want to plead guilty to this - it will give you a permanent criminal record. Not worth it over something so trivial. I would recommend a lawyer - either hiring one or, if you qualify, asking the court for a public defender at your next appearance. They should be able to plea this down to a non-criminal charge, or at least an ACD, for you.
Good luck.