No, it is not grounds for dismissal.
Yes, you can fight it. The best you can hope for is that the officer does not turn up to testify. Then all his evidence (the ticket, recordings) are hearsay, and not admissable.
More than likely, you will get some kind of deferred adjudication, or a lowered fine if you choose to fight it. Depends on the prosecutor.
You can also go and straight up ask the Judge for a lowered fine. I'd ask around about his/her reputation before doing so.
Does your state allow a driving course in place of a fine?