The next day, worried about having too-greasy of hair for school, I doubled down on my hair. I not only washed with baking soda and water, then I washed with the castile/OO/water mixture, THEN I washed with a simple castile/water mixture. I then followed up with an ACV rinse. This did the trick! Clean as a whistle! Although it looked/felt clean, my hair had a ton more body/bounce/softness to it. It didn't feel all dried out as it did with shampoo.
Later that day (day 2), we went to play tennis, so I got sweaty and had to shower again. This time, I only used the castile/water mixture for shampoo and it worked well. Although, using this I don't know if I am still technically "no 'poo." So, next time I wash I am going to do the baking soda and water wash and see if it cleans well enough for me to show my face in the office.
In the meantime, it has been two days since I shampooed last, and already I noticed that my hair is less greasy than it would have been before. Progress! Bow down before me overactive sebaceous glands!