I was just recently diagnosed and only found out more about autism within the past 3 years, but I definitely feel that I've gotten "worse" over the course of my life, too. However, I believe it's because of environmental situational factors mostly... I have become more reclusive because of the fact that I no longer live with or near my family (whom I was close to, they live in another state, 14 hours away), and my only real friend is my fiance whom I am very close to. The lack of ability to make new friends (I'm not in school any longer, currently not working, living in a suburb 30 minutes away from town, I don't drive) makes it hard for me to know how to interact with people these days. Without practice I've not only become rusty but also paranoid of failing and lacking confidence (which just creates a cycle of failure or at least perceived failure)... I also don't fit in with the people I do meet because I lack the level of education and success they have. I'm very intelligent but because of my learning issues and anxiety I only have an associates degree (which even so took me 5 years to complete). Being around more successful people than me makes it hard to interact confidently, or know what to say. But being around less successful or less intelligent people than me also makes it hard to know how to interact. I feel like I don't have a middle ground, a comfortable place I can call my own in society, so I tend to be very self aware of my issues, awkwardness, eccentricities, etc...
I know autism has shaped me but I think the lack of support, friends, knowledge, confidence, and success has shaped me even more. I know all of that is effected by autism, but I guess what I'm saying is I feel like rather than my issues getting worse because of some biological time bomb getting worse, I'm just getting worse because negative event after negative event has made me overly cautious and afraid of negative events. Kind of like if you were to get sick by eating bad sushi, you might be afraid to eat sushi for the rest of your life. Not because it's inevitably going to make you sick, but because you know what it's like to be sick from sushi so you stick to safe foods that have never made you sick, or that comforted you when you were feeling ill...
Defense mechanisms and such... :/
I hate to say though, I agree. I've also gotten worse over the years and not better like some people would have you think happens for adults on the spectrum... I'm trying very hard to overcome my difficulties or at least learn to manage them, but it's not easy. I feel like I handled my issues better when I was a teen because I didn't believe I was the problem, I believed everyone else was! Plus I think being strange was more acceptable as a teen than it has been as an adult.