I wish I wasn't.

In my head I'm still like 16? I know, logically, I have not been 16 in a very long time. I know logically that my body and mind have more or less matured. And that I am a grown ass adult. I do not feel like an adult. I rarely get along with actual adults. I do not really have "adult" hobbies. I still feel like I'm a kid in an adult cosplay and it fucks with me more than it should. I've still got the mindset I did when I was that age. Outwardly time has passed. I am an adult. But in my head I'm still 16. I'm still that overwhelmed kid that worries about homework and school friends and shit like that. Sometimes I feel normal. Like an adult. But most of the time I'm just an overgrown teenager. Is this age regression? Is this just me being a generally fucked up individual? I don't generally interact with actual teenagers (unless they're family) it does make me massively uncomfortable. But it made me massively uncomfortable as an actual teenager. I wish I knew what is wrong with me.