How long married for anullment to be good?

Yes it should be allowed. I believe most states allow you up to 12 months.

There are ver few states left that allow annulments and in those states an annulment costs a lot more than a divorce. You are better off getting a divorce. If you were able to get an annulment, that wouldn't convince anyone that you didn't have sex with your husband. In some of the few states that still do permit annulments, the only reason they will grant them is if one of the requirements for getting married in that state was violated.

Yeah, i'd just get a divorce, it is probably easier.

Depending on what state most Catholic Church laws are under a year with no kids

It probably depends on the state you got married in.

after a few months, it might be quicker to just go down to the court house and get a divorce.