Can I use "I just got 22 years old"?
I got 18 years old today"
//warning: not a native speaker.
"I've turned 22 years old today"(probably more correct) or "I've become 22-years old today".
"Just got 22 years old" sounds like you're talking about somebody else - to me it sounds like "the only person present at this location is 22 years old".
*I got 18 years old today - wrong *I've become 22-years old today - wrong
*I turn 22 years old today - correct *I am 22 years old today - correct
From a native speaker in the UK :)
I would say I turned 22 today.