Is it possible for a resident in a university to give consent to sexual activity with an RA

I am a residential assistant and was accused of engaging in sexual activity with a resident. She claims that I never asked for consent, however I did continuously throughout the night of our encounter and only once did she not give consent and that is when sexual activity stopped. When she gave consent it was either a head nod or a verbal yes. Never an absence of a no. There is also an inconsistency between what she told the investigator and what she told her friends. Any tips on how to fight this would be amazing as I will be trying the case in front of a panel of university faculty in a week or two and attempting to prove that any activity that did happen was consensual and that there was activity the resident claims to have happened that did not.