I'm seventeen, about to be eighteen in five months, and the other day, my mother said that if I didn't prove that I can be responsible with my money, she would stop me from closing my custodial account. Can she do that? We live in New York.
See the article Age of Majority and Trust Termination. The site happens to be college related, but the chart offering age at which the minor takes control of the custodial account, by state should help address your question. For NY, it's 21, not 18. Same in my state. For custodial accounts we have for our daughter, she can show ID and take over at 21 if she wishes. Both smart enough to know she can, and wise enough to put the transfer off.