I changed the practice area to tax because that is the area more germane to your question.
Nothing in what you've described would prevent you and your future wife from filing your taxes jointly; however, you may not want to file jointly because any refund you might be entitled to could be taken to satisfy any tax debts she owes, or any debts she owes for student loans, child support, or to certain other federal or state agencies.
All of that being said, you should really consult with an attorney with experience drafting prenuptial agreements to make sure you get one that'll do what you want it to; and perhaps more importantly, to learn what it won't do for you.
My answer does not constitute legal advice and may not be relied upon by anyone for any purpose and does not constitute an attorney/client relationship or an offer to form such a relationship. This disclaimer is intended to be fully compliant with the requirements of Treasury Department Circular 230 and the terms thereof are fully incorporated by reference. If you wish to consult with me please contact me at dana@nytaxcounsel or visit my website at www.nytaxcounsel.com