Help idk if im lesbian or if im bi ! ?

I watch porn and i think everyone does but everytime in there im always interested in the lesbian categories n i have dreams of me having sex with another girl . Idk if i just like oral sex n the feeling of someone fingering me or its just that im lesbian . 
​I like penis tho but idk theres something i like better about lesbian sex it just turns me on . Please help ? Any lesbians out there ? How do u know u are ?