I still find "magical" aspects about the special interests I had as a child such as roller coasters. I used to live and breathe roller coasters ... all the way through college. As I matured as an adult, I didn't spend as much time with researching and riding them. However, something else sparked my interest -- collecting vintage roller coaster blueprints. Although I spend little time thinking about these rides, I did start an HO scale roller coaster model last year that has most of its major sections built. I still like house plans and blueprints for them, but I don't collect house plan books anymore, however, I will try to get an occasional mid-century style blueprint when available.
My big thing now is writing. I find writing as an escape into whatever world I want it to be. If all is quiet in the house, an I submerge myself deep enough, I can quite literally feel like I am living the story I am writing.
So, to answer your question. Have I grown out of having special interests? No. I still get overly fascinated by topics. But my approach to them has changed.
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"My journey has just begun."