US Airways status resets every March 1st. So, I am pretty sure that as long as you have a Cent card prior to 3/1 that your status will be good through the end of the plan year (2/28/15). My guess is that any new cardholder, who joins prior to 3/22/14, will also get status through 2/15.
I don't think that US Airways has a way to terminate FF status mid year. I know that when we have cancelled someone's Cent card mid year they were able to keep all of the FF status until the end of that plan year.