Without pictures, we're just guessing. That being said, unless the bumps are extreme, I doubt you will ever have any cracking problems, or if you do, it will be after thousands and thousands of kilometers.

If it does crack, I doubt the frame is worth repairing. Very few bikes, unless they're extremely rare / valuable, or have sentimental value will ever come close to recouping the costs of a decent frame repair / repaint.