Datun yeh, essentially. All we have to go on as humans is our experience up to the current moment. If you've never experienced sexual attraction to a woman (as a woman) it's reasonable to ID as straight, then you meet one woman and you're not straight...or maybe you are, just not for this person. Labels aren't concrete IMO, things can always change because not all women are the same (or men, or redheads, or whatever).
Romantic attraction and sexual attraction are also different, maybe you can see yourself being in love with a woman, but don't want to have sex with them, you'd quite like to marry a woman, or live with them, cuddle, kiss, care for, have babies with etc... but you're not sexually attracted to them.
Sex and love aren't combined for everyone, especially asexual people. Also love, for aromantics, doesn't always mean the same as it does for sexual/romantic people.
I am not romantically attracted to men, for now anyway, I do want to get married, have babies, be in a relationship, with a woman. But I don't want to have sex with them, or rather if I did have sex with them it would be because they wanted/needed it rather than because I did.
The masturbation question is also interesting, because I don't masturbate and never have, it does nothing for me, and I really feel that is because I don't experience sexual attraction. But some asexuals do masturbate, despite not being sexually attracted to other people.
Brains are weird