I graduated from CS in the fall of 2010.
The classes are composed of a lot of lecture and projects mostly. There was a little bit of homework, but not overwhelming. They usually give you ample time to complete projects and homework. I am talking 3 to 4 weeks per project, so as long as you stay on top of it, you shouldn't have to stay up all night often or anything like that. You don't need any experience whatsoever, they will start you at the very bottom of teaching you what the word "programming" means. You will most likely start with Java though, because they start you with the most current rudimentary language, then once you have the basics, they will move you into the object oriented world and the most popular languages like Visual Basic, C++, C#, and ASP.Net.
We started with about 6 girls in our program when I started. When I graduated, there were 2. The guys aren't as weird as you would think. Not like revenge of the nerds or anything. Windows machines will definitely be easier to deal with. You are creating a huge headache for yourself if you go in with a Mac. Plus, most universities offer a software bank, which in my case, only offered Windows based software.
You will enjoy it! It's awesome stuff to learn and when you create those applications, it's awesome to show people your code and have them say "oh my god, I don't know how you can understand that". haha. If you're interested in the field of CS, then it will be great and you will love it. Plus the money is pretty good. I live in the low end of the national salary average and got a job 1 week out of school making over 50k.
The scariest part of it were the exit projects, when you had to do a semester long project, which comprised of coming up with your own, new idea for something, and do the entire project yourself, documenting as a professional, creating the 60+ page documents (mine had 3 separate documents for a total of over 190 pages lol) and designing documents and testing procedures. It was pretty detailed. No one told me about it until I was almost to that point, so I was very scared. I literally did not think I could do it, but somehow I pulled it off. You can do it, it's not that bad and you will be very happy you went through with it.
Let me know if you have any other specific questions and I will be happy to help.