The crush theory is sound, but in other stories this is explained like guys being horny...and girls being too, they simply keep it covered better to not being perceived as whores.
The stress of faking being a guy and being unable to do stuff like a normal girl got to her head, she got clsoe to Dino for him knowing her secret, it does work on paper but is a bit too fast.
Still, better than other stories I read where similar stuff happens and the 2 parts don't go anywhere for years.
"Now we both have a secret"...girl, the first secret is bad for you, and the new one is too.