They hired me two years ago without it and trained me on their dime about a month after I started. They hired my wife last year and gave her enough time to get trained. (She elected to pay $99 to get trained by people from Wilkes-Barre in King of Prussia rather than going all the way up to Brooklyn to get trained for free by CVS, but they did offer that to her.)
Even if you can't get them to train you, just sign up for the classes they will surely have available come June for all the new grads. At this point, we are past the prime immunization season, anyway. Being certified isn't going to be a huge issue until next September. As long as you can reasonably be expected to be good to go for next flu season, you'll be fine.