It's common for both autistic and neurotypical young men to get to your age and have little to no romantic experience (despite what they might say). People have different ideas of "friends" so it's hard to say how many people truly have friends and how many friends they have. I THINK (I don't have any data to back this up) that neurotypical people are more likely to call people "friends" when it might be more appropriate to say something like "acquaintance" or "classmate."
It is pretty common for autistic little kids to take awhile to potty train and have other developmental issues. My personal opinion is that this is because they are handling other developmental things and what might seem important to most people is relegated to a less important milestone to the autistic child. For example, let's say that a little kid is having trouble with sensory overload, which makes him feel like he's being attacked all the time. It may be more important for that child's wellbeing to build coping mechanisms such as stimming or withdrawing when overwhelmed. Someone will eventually change their diaper, but it may be that no one understands them well enough to rescue them from the sensory overload.
Plus, I am currently potty training my two year old. He is neurotypical. I have to train him early because he's abnormally large and won't fit into training pants anymore. Picture The Hulk as a toddler and that's my little boy. But anyway, it's really, really hard to potty train some kids. If I couldn't talk to my kid and he couldn't talk back to me, or if he was dealing with sensory issues and other common autistic differences, there's no way I would try it at this age.
If I had to guess, I would say that your mom feels guilty that she "failed" with some of your developmental milestones, so is blaming you because she secretly feels SHE is to blame. Really, no one is. You sound to me like you are on track.