Ditto to the above - search before asking a question that might have already been asked loads of times.
It's no problem to ask questions, that's what the forum is here for (well that and chatting/procrastinating).
when I first started Med chool, we went to the dissection room on the first Friday we were there. At least 4 fainted and 2 ran out screaming. OK, I have to be sexist and say that they were mostly female. However, they are all still here, finished the dissection and some have even been to Post Mortem examinations, which believe me are so much worse than dissection.
You will get used to the body, and start thinking of it as an item to help learning, albeit one to be treated with the upmost respect, so you will get on with it. But be warned, you will never ever get used to the SMELL - it isn't as gross after two weeks but its still always there!!
Just don't have any premonitions or start thinking up reasons or scenarios before you've even experienced it. It won't be anything like you expect (that's a good thing) - it isn't that bad at all.