It could get worse and a case could make it worse if it is a tight fitting case.
iPad screens do NOT typically crack on their own.
Please do what ProustGuilio recommended.
Unless you can prove to Apple/Apple employees that this screen crack is a manufacuring defect, you might have to live with this crack or pay an expensive, out-of-warranty device replacement cost or maybe plead your case to Apple/Apple employees and hope they might give you a free, replacement iPad, since this iPad is still within the 14-day return policy window.
Best of Luck to You!