I live in New York. New York law states child support shall be paid until said child turns 21 years of age. Is this true if they go away to college?

Generally support continue to 18 or when school is finished.

Check this: "When are my children emancipated, so that I am no longer obligated to support them?
A parents liability for the support of his or her children is limited to children under the age of 21 years. In the absence of an express or implied contract, parents have no duty to support an adult child. For custody, visitation and other purposes, the age of majority is age 18, but for purposes of the parental support obligation the age of majority remains at 21. The mutual parental duty of child support is not absolute. It may be suspended or terminated before the child is 21 if the child becomes emancipated by becoming economically independent of his/her parents through employment, by marriage or entry into the military service. Under unusual circumstances, a child may be deemed emancipated if he/she is guilty of outrageous misbehavior, such as makes it inequitable to enforce the support obligation, or if without cause, he/she withdraws from parental control and supervision."
DivorceNet - New York Child Support FAQ's (http://www.divorcenet.com/states/new_york/nyfaq01)