I'm with you on this being incredibly exciting.
I'm 40 and have been doing this since I was 12 as well. Once I became a staff engineer at a large company and ended up being a less Hands-On with code and more on team leadership and system architecture, it set me up for this perfectly.
I missed writing code (or so I thought) but what I realized is that I actually missed bringing ideas to life. Coding was just a means to do that and the new tools with LLM and agents have allowed me to do the core of what I love way more than coding by hand could have ever allowed
Same boat (though 44M) - I don't think it has become less fun, on the contrary it can help with the stuff that was trivial but could still take time to get right. Now it can crank out that stuff often correctly on first try. Of course I have the same fear of job security as everyone else and it is sad to see something you were good at being taken over by machines, but it is not because I enjoy the work itself less, quite the contrary.