First off, good for you for reaching out for support; that's very often the hardest part.
I understand your frustration at never having a girlfriend and still being a virgin at 30, but, speaking as another fella, I honestly don't think you have anything to feel embarrassed about. We all too often compare and judge our lives against the lives of others around us which, very often, leads to misery.
Given that you have been so busy with your studies, it comes as no surprise at all that, unlike some of your peers perhaps, you graduated from university still single. I doubt for a minute that you were the only single person that graduated that year; I also doubt very much that you were the only virgin either.
If you were ever to tell a "mate" that you are still a virgin and he/she responded by saying anything other than something like "there's nothing wrong with that, you obviously haven't met the right woman yet" (I hope you get my point), then I would question just how much of a mate he/she is. As for any woman thinking you are weird 'cause you're still a virgin, would you really want to share your body with someone that shallow? I'm guessing you wouldn't as it's more than a one-night-stand that you'd like.
I think a key thing to remember here is that even though women can be as (insert adjective of your choice here) as men, most men and women look at sex differently. For a lot of men, sex is in the penis and their biological need to reproduce whereas for a lot of women, so my female friends tell me, sex tends to be more in the brain which is why, so my female friends tell me, if you do not turn a woman on mentally, it can be quite uncomfortable for them. Truth be told, women, as a rule and in my opinion, tend to be more mature emotionally so they are less likely to judge you than another man might, on account of him buying into the bullshit that is toxic masculinity. You are no less of a man because you have never had a girlfriend and are still a virgin than a man that has had 100s of women from the age of 16 is.
You say " I really cannot understand why I got in this situation. I was born a very shy, introverted person who was extremely studious and naturally had social anxiety." I would suggest that therein lies your problem. If you could build on your confidence by pushing yourself out of your comfort zone, perhaps by being a bit more open to hobbies that aren't male dominated, you might find that you get to meet more females. If you could also work on your social anxiety, things would have a better chance of falling into place for you eh, especially now that you are no longer studying.
I'm no expert on anything, but, I do believe that there is a solution for every problem and I very much hope that you find one that best suits you and your needs.
Good luck fella!