It's a tricky question and I'm not sure after reading this you'll get an actual answer (full disclosure) but it's bugged me for a while, as a person and as a teacher. I had a friend who wouldn't train to be a teacher after university as she didn't feel like an adult yet. At the time I told her I'm not sure you'll ever feel like an adult but believe it or not you are one.
The law says you're an adult at 16. You can get married, have sex, move out of your parents house and be tried as an adult in court. Looking back at 16 year old me, I was battling with an eating disorder, hasn't even taken my GCSEs and was constantly arguing with my parents. Was I an adult, legally maybe, but really? No. I had no idea about anything, I could tell you a lot of facts, blow your mind with mathematics but in terms of surviving on my own, I'd be lost. Although my sweet 16 was a murder mystery dinner party, so at least there was hope!
If not 16 then 18? Now I can drink, I'm in college I had my first actual job and I had a car and could drive. I'd also already crashed said car and called my dad first, before the insurance or police, so again maybe not. I'm also pretty sure you couldn't call me an adult after seeing the silly things I did whilst drunk. I mean I broke bones, plural. So for some maybe 18 was when they felt like an adult but for me, still living at home with my leg in a cast, I wasn't feeling very adult. I was however feeling pretty independent, I had a car after all, I could go wherever I wanted, and I did. I visited friends in far places and possible universities, I think if you'd asked me back then i might have said I was an adult but hindsight is allways 20 20.
I was one of many people who took a gap year before university as I didn't get into medical school, so I had my job and even a second job. I was a playworker at an afterschool club as well as a receptionist. But I'll be honest, all my money went to my local pub, I didn't travel the world, though I did travel England. After my gap year it was university, I moved out for the first time and had a budget! I definitely felt more independent, but my parents still gave me an allowance and I was living with a lot of other people. I joined clubs and became a leader in those clubs, I even became the vice president of sport for my entire university! I began to feel responsible and dare I say, like an adult.
So 22 I guess for me is when it started. I started to feel like an adult. After university I went straight into teacher training, and let me tell you nothing will make you feel less like an adult than hanging out with children all day! I was not ready to become a role model! I was still getting drunk, I didn't have my life under control, in fact it was falling apart. So not 22, no definitely not. That was just a momentary illusion!
I feel like my first year I kind of blagged being an adult and the second year I had 2 personalities, I was an adult at work and just shy of an adult at home. I still watched Disney movies, let my parents pay for things and was still figuring out what I wanted from life.
Now half way around the world at 25 I find I'm in the same position, I still don't know what I want yet. I have a thousand options and I don't know which to choose. But what I have realised it's that I was right years ago when I told my friend you'll never feel like an adult, but you are one. I get it now. I am an adult, and sometimes I feel like one, sometimes I don't. I'm on my own, independent, I'm budgeting, planning and surviving. I also don't have a job, don't have any real bills and miss home, a lot. I know I'm an adult, but it doesn't always feel like it. But I bet my Mum feels that way too, and I bet I'll still feel that way when I've got kids of my own.
So the moral of the story? Enjoy the things you enjoy, if you want to act like a kid, do it. But I'm sorry to say you are actually an adult, but that is just a word, it means nothing! Thank goodness!! Now to watch beauty and the beast :-)