Travel / Krakow or Warsaw for a 25yr old? [12]

Hey everyone, I am of Polish ancestry and I am taking a short trip to Poland around Easter. I haven't been to Poland yet and unfortunately stopped speaking the language after all of my relatives passed away. I can't decided which would be a better place to visit, Krakow or Warsaw? Although I am going for the history, let's face it, I am young and want to go to the city with the best nightlife also. Please help me out! Thanks a lot!