Okay. Well resistance at first to the idea is fairly common among significant others and spouses, as I understand it. They're going to have to make sacrifices too, and it's so that YOU can change careers. So their first reaction may not be ideal.
My advice:
Do not let yourself become annoyed or angry about the initial lack of support. She sounds concerned about you and about her family, and, quite reasonably, about herself. It IS a long process, it IS expensive, and it WILL take a huge amount of your time, especially if you're working 8-5.
So, assuming you've done a lot of soul-searching, and a lot of research, sit down with her, and CALMLY discuss it. It is imperative that you stay calm, and rational, and understanding, throughout the discussion, regardless of what she says or does. Try to understand her concerns first. Ask questions. Re-phrase what she's saying, and ask if you're understanding her correctly. That will establish confidence in her that you do understand her concerns, and can be responsive to them. Okay. That's Phase I. Phase II is discussing her concerns, one at a time. Be diplomatic, be fair--this is going to involve some sacrifice--but if it's doable, explain WHY it is doable. If this will involve a long-term payoff, explain that. Explain how this will fit with the daily schedule and routine. Explain that it will be good for your child to see how dedicated and hard-working you are. Explain the importance of it to you, and how it will enhance your life and your relationship.
I'm assuming you can explain all those things, and that all those things are true. There really are only so many hours in the day. If you don't yet have an answer to those things, my advice is simply to mention to your wife that you've really been thinking about what she said; and then have the conversation at a later date, when you're ready.
Hang in there. I know that this is a tough thing to consider when you encounter resistance at such an early stage.
And to the attorney above (I'm also an attorney) who pulled off the pre-reqs while working as an attorney, WOW. Nice God damn job.