You know how men sometimes get erections when they wake up in the morning, regardless of their state of arousal? This is called arousal nonconcordance (when the body’s arousal response does not reflect the psychological state of arousal and desire) and it can happen to women, too!
This means that a woman’s vagina can lubricate in the absence of arousal, or can be unlubricated even when a woman feels super turned on!
There’s nothing wrong with you if your body isn’t responding to your brain, just grab some lube!
You are normal.
Check out the paradigm-shifting science in Emily Nagoski’s book, Come As You Are.