It's normal from a self-preservation aspect to be wary of getting involved with someone who isn't sure of their sexuality or experimenting with it but it's never, ever, okay to deny someone their feelings. How can you be so sure about what's inside someone else's heart?
None of us were born into this world knowing everything about ourselves. Life itself is a constant journey of self-discovery. Rejection by deflection is cruel.
I'm glad the misunderstanding was cleared quickly.