So you like gay porn and you like women. While that's not a "conventional" set-up, it's certainly not the oddest the world has seen. You seem to be overly occupied with labels. Don't concern yourself with what the rest of the world will think; just be you.
While watching a lot of gay porn may desensitize you to it, watching it can't "make you gay." I'm a firm believer that human sexuality exists on a SPECTRUM and is NOT an either/or proposition. While sexuality can also be somewhat fluid, my opinion is that one's sexuality is "hard wired" from birth (Again, this is my PERSONAL opinion; I have no hard scientific facts to back this up but living as a gay man for 50 years does afford me SOME manner of experience in the field...) So, if you have gay tendencies, it's not that you're BECOMING GAY but that you're discovering that part of you which has always been there. And there's nothing wrong with that.
Some people don't discover and accept their gayness until very late in life. Mostly this is due to societal pressure and dogma that says "gay is WRONG" and they spend their entire lives trying to reconcile their inner feelings with external influences and beliefs. In a society where sexuality isn't such a flashpoint of controversy, your seemingly dichotomous attraction to both women and gay porn wouldn't be a problem. People would just accept it as a characteristic unique to you. Unfortunately, we don't live in that world and people WILL judge and criticize you for something THEY don't understand.
But YOU have made it very clear that you like what you like. And that should be enough for you. It may not be right for OTHERS< but it's OK for you. So go and be you; don't let anyone else tell you who or what you can or can't be.