I agree with Pinetree. Although I understand the feeling to "fight" this, I would not want to use that language. What you resist persists - the fighting paradox in the therapy.
Self-acceptance does not come overnight or by force. It will come if you work on it daily as you work on the therapy. It won't come by some external idea of success or failure, gains or losses materially. It will come from within you as you start to believe it. Also, I do not mean this to sound like some sort of best-selling "Love Yourself" pop psychology. I don't think social anxiety sufferers get to the point of overcoming social anxiety simply by accepting the rational idea that we should all love ourselves. I do think the perception of the world and self-acceptance is important, as is stated in the therapy, so it has to be worked on actively, just like the other techniques.
You state that you are a decade behind others. Well, there are ways to allow that to fester or there are ways to see that from a neutral perspective. It doesn't help us to measure ourselves in this way. There are plenty of others who may be happy to be in an outlying category at a certain age, without regard to anxiety. You say these bench markers are used to define one's worth? By whom? Who is doing the judging? I'm not. I used to be to myself. Yes there are societal pressures, and expectations. I don't deny that. But we also work from where we are right now. We start here and work towards solutions. We get nowhere with such value judgements placed on ourselves, with guilt about the past or feelings about perceived failure. The biggest influence that is defining you by your worth is yourself, not others. Your definition of yourself is what is most important. To change that in a healthy and rational direction, we must turn to a learning therapy - CBT. Slowly learn new habits, slowly retrain the thinking and feeling and reactions we have. That is the structured goal of the audio therapy series.
So fighting, although we all understand this feeling, won't get us where we want to go. You may be going there while fighting, but at some point the issue persists exactly because of that fighting. And to change your life, I would ask you to think how you plan to do that? You don't need to answer this here. Think for yourself. Will you create a structured daily habit or lesson plan for yourself to begin this rational re-learning/thinking process? Will you simply try to force yourself into situations? Notice the word force. Force = fighting.
I wish you the very best!