Will my case be expunged when I turn 18?

If you are given juvenile offender treatment then you won't end up with a record. There is no expungement in the State of New York. If's more that you haven't been in trouble before that will help rather than any of the things you mentioned. As for an ACD, an ACD is where your case gets adjourned, usually for a year but sometimes less. If you don't get into trouble while the case remains open, then on the adjourned date the case is automatically dismissed. You usually get offered only one of these and very rarely a second. But, penalties depend on a lot of factors, including age, criminal history, severity of the charges, amount of pecuniary loss involved, character and remorsefulness of the defendant, how egregious the facts are, was anyone injured, has the defendant cooperated on other prosecutions, etc. I can't offer an opinion without knowing all of the details.

These are serious offenses and you should not attempt to proceed without a lawyer. There are many possible dispositions including an ACD. Your background is always helpful in obtaining a favorable disposition. You are 16 and therefore you also qualify as a youthful offender. With a youthful offender disposition it is not considered a crime however your record would always be accessible as part of your RAP sheet.

First, NYS does not allow for expungment. Second, you are 16 years old and are likely eligible for "youthful offender" status, depending upon the severity of the offense. You need to find an experienced criminal defense attorney to get you the best deal possible.