Here are my thoughts.
I wouldn't have a newborn at any point during nursing school. While finishing your pre-req's, yes, maybe, but not during Nursing school.
I had my daughter last year in September. I was lucky enough to be taking an online course (actually 2) at the time. But I will tell you, with the sleep deprivation and the needs of a newborn, if you are in the actual nursing classes, I don't see how it's possible. I'm sure it is, but it would be extremely hard. Your newborn is going to need YOU after he/she is born for quite some time.
With my daughter being 1 now, my DH is able to take care of her more often than when she was newborn. When she was newborn, he didn't know what to do for her - Mommy did everything. So, really think about it. It looks like your saying you would start the nursing classes in Fall of 2007 (but then you said something about 2 1/2 years, so I got a little confused). Just remember that the Nursing portion is going to take up much of your time and like the pp said, a child won't wait!! Especially at such a young age!! Newborns are very demanding!
In my honest opinion, it would be much easier for me to get through school if I didn't have a child. I absolutely 100% love my daughter and wouldn't trade her for the world and wouldn't change a thing, but I have been through school both without and with a child and I will say, without was much easier, and I am only referring to classes that didn't require too much of my time...once I start the nursing is when the real test will be, but with even just the pre-req's, it's a challenge. (Especially with a DH who doesn't offer his help very often).
Just really think about the time you will spend away from your child with school. It's going to be torture for me when I have to leave her for so many hours. The years you spend in school will fly by, then think about kids.
Good luck in whatever you decide, but I would say just wait. No reason to rush it if it's not necessary...JMO. (and for the record, my daughter was not planned...and as I said, I wouldn't change a thing).