I wouldn't worry too much about the germs or sleeping with it. Just keep the kitty stuff relatively clean, like Jennyranson suggested, and you could put a mat under or in front of the litter box so that the extra litter on her paws are left on the mat as she steps out, instead of tracked around the house.
Also about germs, you don't have to let kitty eat or drink from your own dishes, and you don't have to kiss her nose, other that that remember that humans build resistency to most germs. I would not worry about it. Just enjoy this wonderful companion you have!!
Sleeping in your bed, what nice company!! Don't worry about the germs, humans are full of them also......... And you probably won't roll on top of her, most of the time people will subconciously know not to, even in their sleep. HOWEVER: If there is alcohol or drugs involved, people may become sluggish and not so aware of themselves anymore. But for you, it sounds like you're just not used to the idea, but I'm telling you it's a fine idea! You may come to really love it! When I first married my husband, we both had a hard time sleeping because we were used to sleeping alone; but now we sleep better when we're together (or at least I do) because that's what I'm used to now.
Having a cat in the house will take some adjustment if you're not used to it, but just give it some time and it'll be great! Do alot of reading though, it's very helpful. I got a book at the library called "Complete guide to cat care" by the Humane Society of the United States, and that was a very good, fun and educational book to read. It'll teach you everything you need to know, although I don't think you need to do absolutely everything they suggest either. They go by what the ultimate perfect conditions would be, and personally I'm not able to provide all of that, I just use common sense and my judgement in what I need to do, + your vet will be able to give you good suggestions as well.
Best of luck to you, I hope you'll have a wonderful experience with your new cat!