Is it considered a repossession if you take the car back before first payment is due because dealer lied about what he would do to and how many miles were on it?

It highly likely wouldn't be considered a repossession, as you are voluntarily returning the vehicle before the first payment is due. However, the exact characterisation of the situation may depend on the specific laws and regulations in your jurisdiction, so it's best to consult a legal professional or consumer protection agency for accurate advice based on your location and the circumstances of your case.