Not an immigration question. Therefore changing the practice area and removing the immigration tags.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.
You ask a great question - this is an area that's often misunderstood. The right to claim a child as a dependent is a function of who provides the financial support and a number of other factors. Each person only gets one "deduction" so if you claim yourself on your tax return, your parents can't claim you on theirs and vice versa. So being married or not, filing jointly or not, all have no real bearing on who gets to claim the dependent deduction.
So in this case, if you were married by the end of the year and filed a Married/Filing Jointly return with your new spouse (Congrats by the way!) they can still claim you as dependents, so long as they qualify and you don't claim yourselves as dependents.
Hope that helps.
Disclaimer: I am not your attorney. My response is provided for informational purposes only and does not constitute legal advice.