Most people in their twenty a are into casual sex and they sometimes use that as a measuring stick to see what they are looking for I'm 24 soon to be 25 and I never had casual sex never been interested. I also have never dated before. I don't have a social circle for the most part I just go to the gym work and then return home and repeat everyday until school starts then it changes up a little but my love life is non existent should I be concerned as old as I am that I never had one girlfriend before or that no girls know I exist
It doesn't seem like you are wired differently but rather that you haven't put yourself out there or really had much opportunity to do so. There's a big difference between not being able to get a date and not being a situations to get one/not trying. Dating is very much a numbers game nowadays. That doesn't mean sleeping with a bunch of people but rather being able to meet all different kinds of people so that you can eventually find one who is compatible with you.
I'm in my 20's and I'm not into casual sex at all. The idea of it just doesn't appeal to me in the slightest. I think maybe you should consider joining a club or taking up a new hobby that will allow you to meet new people. That way you could get yourself out there to find a girlfriend.
Everyone is different when it comes to their love/sex life. The question shouldn't be whether it is normal or not, but rather are YOU happy with your life as it is? I myself didn't start dating until I was 25, because I was focused on graduate school and didn't have much of a social life. I then decided to pursue online dating because I felt like something was missing from my life, not because I felt it was something I had to do. If you feel like you want to get into the dating scene, do it for YOU. Its never to late to start :)