How marvellous to hear your thoughts about Baptism.
As one who predates you by a whole month (!) I too have had to consider this amazing and mysterious gift from God. Only the other day I wrote some notes in another place, and though far from as eloquent as your posting it is clear that we have both experienced change, perhaps a little unexpectedly.
As a lifelong Christian I suppose I felt that I 'knew' Christ already, so there was not going to be much for me to learn. And I 'knew' about the theology of Baptism. How wrong can one be. Despite my infant Baptism in the RCC which had brought me into God's family, there is certainly something different about me now that I am Orthodox. However, it is taking me some time to figure it out - always assuming that I will ever do so.
Like you, although I approached total immersion with some trepidation, it was actually a profound experience. My infant Baptism had a profound spiritual effect, of course, but I was effectively unaware of it, or perhaps more accurately I had no idea what life was like without it. Now I have had to make a conscious committment to Jesus in a manner completely new to me. This has allowed me to compare my new situation with my former life. Not being critical of the RCC, which nurtured and cared for me very faithfully for all those years, but still it is not the same now.
Although I am still working things out, two points stand out at present.
First, I have a feeling of joy which I had not experienced before. Yes, I had been joyful at various times, but not like this, and not so constantly. This sense of joy was also evident in the sisters and brothers we met at Stevenage, and seems to be a characteristic of Orthodoxy. This has caught me by surprise, because my stereotype of the Orthodox was a stern, rigorous institution run by black clad clerics who seldom smiled, let alone laughed! It is wonderful to be part of this uncomplicated joy expressed by all the people .
Second, I have a new prayer life. Not only is the emphasis of the prayer different and in keeping with my acknowledgment of my personal sinfulness, but it has a new intensity which has brought an interesting consequence. I find my prayers are always being interrupted or distracted, and clearly Satan is getting worried! I comfort myself with the thought that if that is the case I must be doing something right! And every time it happens, Jesus bolsters me up as I reject Satan and tell him to be gone.
So, Baptism is all those things you mentioned, and then some more. So much more that I cannot begin to understand it, but I let the Holy Spirit wash over me enveloping me in His inexpressible love. I have a renewed sense of Jesus being close by me all the time, defending me from Satan, despite my best efforts to keep on sinning, and constantly forgiving and healing me. I believe you are right when you imply that we will probably never understand fully what Baptism does for us, but I look forward to many years of exploration, together with you and all my other sisters and brothers Christ.
With much Love to you, my new Brother in Christ,
With love and prayers,