The NOvA experiment is a long-baseline accelerator based neutrino oscillation experiment. It uses the upgraded NuMI beam from Fermilab and measures electron neutrino appearance and muon neutrino disappearance at its far detector in Ash River, Minnesota. Goals of the experiment include measurements of theta13, mass hierarchy and the CP violating phase. NOvA has begun to take neutrino data and first neutrino candidates are observed in its far detector. This talk provides an overview of the scientific reach of the experiment, the status of detector commissioning and the preparation for the electron neutrino appearance measurement.