Should we preempt Topicality in the 1AC with definitions?

I would use definitions in your 1ac only if other teams use/judges expect definitions in your area; let the negative advance contrary definitions and then you can provide your own. I would, however, recommend putting evidence in your 1ac that says your plan is an "education policy" and that you are a "change" etc. so that you can refer to it in your 2ac/1ar/2ar.