Cdl requirements in NY?

[Ian]

I'm really excited because I just got my CDL Class B permit the other day. I live in NY and I know that you have to be 21 to drive a school bus. The thing is that I took and passed the written tests for the air brakes, passenger, and school bus endorsements. What I need to know is if I have to be 21 to take the road test in the school bus? I am thinking that I can because why would they have let me get the S endorsement in the first place if I am under 21? Maybe you only need to be 21 to drive a school bus with children, and not for purposes of driving it for a test. I have called the DMV and they all give me different answers, I need to know if I can take the test in a school bus and not look for work as a school bus driver until I am officially 21. Please answer if you have any idea what can happen. I am 19, the permit is valid for 1 year and expires 2 months before I turn 21 so just in case I am not able to take the test in a school bus can I renew the permit without having to take the written tests again? Thanks in advance for your answers.