How bad of an idea is it to switch my major in my senior year?

I've been undecided about my major pretty much the entire time I've been in school. I finally settled on management with a concentration in accounting and swore that i wouldn't change majors again but even though I like accounting, I'm not too happy with it. I never considered nursing before because I used to say I would have to be a doctor if i went into the medical field. Ive taken the time to learn more about nursing lately and I think I would love it. SinceI changed my major several times before, it will probably take me an extra year to graduate. I was thinking to finish my degree than enroll into an accelerated BSN program but I'm really anxious to start working. So is it bad idea to switch majors now and to start over?How bad of an idea is it to switch my major in my senior year?
If you have the time and money to spend, and you are confident in the choice you are making, then go for it. But, at this stage in the game, don't make a decision like that unless you are very, very sure of yourself.