When was the first time you really felt like a grown up (if ever)?

I’d say the first time that I felt like a grown-up was the first evening I rented a hotel room for an overnight trip as an adult. I thought to myself, I’m grown up now, someone will actually rent me a hotel room!
Never mind it was a dumpy Motel 6, that looked similar to this picture. It was no treat, but at the time I thought I was the coolest.