April contract will cease to be the front month and it will "roll" to the May front month around the 17th-20th of March. You just need to watch the volume traded at the nearest few contract months and trade the one with the most volume, assuming you are trading directional outright.
I'm not sure about other brokers but in case you are using IB you can see the relevant dates in TWS by double clicking on the contact name.
Negative. NEVER EVER feel "stupid" about asking a question. The stupidest question is the one never asked when you don't know the answer. You need to learn that lesson hard. Ask away. Please, no matter the topic. Always remember... The dumbest questions are the ones never asked. You learn that, you live longer!