Dilemma

Problem: I was offered my first nursing job at hospital A and moments after I accepted it I learned of another, much more desirable position, at hospital B. I applied for the second position because it's really my ideal job situation. However, I am now getting ready to start orientation at hospital A. If I get an interview at hospital B, is it morally right for me to go? Would it be horrible to accept a job with hospital B? I expect to get an interview and feel pretty good about my chances for getting the job for reasons I can't share. But I also feel guilty about potentially resigning from the perfectly good job that I have now.

I would appreciate opinions from the wise and experienced nurses here on AN.

Thanks!