It's interesting how different our approaches are regarding when we consider ourselves adults. Some make the assessment based on when they took on adult responsibility. Others when they reassessed life after a tragedy. I was thinking along the lines of when you stop being interested in doing fun or silly things like you did as a kid. Like climbing trees. Or playing games. Or having a pillow fight.
I had to grow up earlier than I wanted to because I had to take care of my dying husband in our early 20s. Many years before hospice became a thing. He finally succumbed to cancer at 23. I've taken care of 3 dying family members over the years. As y'all know, it's physically and emotionally grueling, so I always dreamed of fun ways to counterbalance that responsibility. If I had a decent climbing tree, I'd go out and climb it right now. But not before I queued up 911 on my cell. The old gray mare....
As far as I know I don't have a doppelganger. One of me is quite enough.
Although someone told me that I favored Kathy Mattea in my youth.
I can't think of anything I'm snobby about. Heck, I drink boxed, cheap wine over ice!
Given your description of grown up...probably in my teens. But truthfully, sometimes I don't feel grown up...even today.
I'm sorry about all you have gone thru. It's so very hard to take care of a loved one. It will grow you up really fast.