In our case, our DS5 has attended K in a school district in NH without any GT program whatsoever. We broached the subject of our smart little boy early in the school year, and seem to have been identified as pushy parents. Which we might be.
Our son was assessed under the local procedures for assessing learning disabilities, since the main reason for using assessment tools in place at our school district seems to be for diagnosing disabilities and making sure kids don't slip through the cracks and get "left behind". Though we began discussions at the start of the school year in September, the assessment results did not come back until mid-November, and we only recently got the go-ahead for a grade skip. We would have been further behind if we hadn't spoken up early.
I can't think of many downsides to opening a dialogue with the school early in the school year. I can only think of one biggie: they may peg you as a pushy parent. The extent to which that is a risk depends in part on the extent to which GT services are provided and/or taken seriously at your school. Anything objective you can bring up may help, as may work samples. In any event I think it's generally impossible to avoid any risk during advocacy, and it's better to get the gears turning than to wait and pray.
Would testing be a possibility for you? Numbers are harder to discount than are parental anecdotes about a child's abilities.
