I bought my first home when I was 22. The day I got the keys and had something of my own I couldn’t just walk away from easily I felt grown up, kinda :)
We were having a family crises and Mom and her sister seemed unsure about what to do. I offered to handle it and for the first time, they let me. Even though I was middle-aged, it was the first time I felt like the older generation saw me as an adult.
Really quite subjective don't you think? Because there is a continuum through the years which makes it possible for me to sometimes still think of myself as a "child" though I am no longer and have not been for many, many years. Leaving home at age 17 was a step. Living with a men lots older was another. Having to wear adult female clothing for a job was a milestone. But I think for me it was mostly being able to become at last self-supporting which was not until I was well along in my 30s, and then. working along, that I was actually doing very well which was in my 40s. And marrying and purchasing a home with my husband at 53. Oh does menopause count?
Only you could decide which event it was. All of what you describe seem plausible, though I think it fair to assume you had consciously shed childhood long before menopause.
There is something referred to as "beginners mind" which is a very young thing. All enthusiasm an enjoyment, eagerness to learn and understand. Though may be an illusion I can't help thinking there is a lot of value in it even becoming older and wearier.
Being present for the birth of our first child. I was a parent, and filled with a need to do for somebody else, far more than I felt when I first got married. So tiny, so precious, so helpless, so utterly dependent - and I wanted to be depended upon.