IIN that I am not the option for relationships?

I believe most people around the age of 18 are yet to have the ability to understand the concept of introversion, or really any personality that doesn't conform to the majority. If you can, read "Quiet" by Susan Cain. It might help you understand yourself a bit and get bits of self-reassurances. It made me realize that I faked being an extrovert a lot in my teens, because I thought it was weird that I wanted a lot of alone time, or that I preferred low-key outings and small groups way more than flamboyant parties or large gatherings. Or that even though I was a chatterbox, being silent with someone was so damn comforting instead of awkward.

It can be tricky finding the line between people trying to change who you are, and pushing you out of your comfort zone. Consider yourself unlucky because all the things you describe about you -- interest in physics, philosophy, sci fi films, excitement for knowledge, non-obsession with makeup -- all make you very interesting and dateable/friendable in my book. And I assure you there are others out there who will feel the same, it's just a matter of you meeting those kind of folks, which can be difficult/delayed when you enjoy being alone.