“Leader” is a title, leadership is taking responsibility
I could prepare, read, study, interview experts, take a standardized test, get a degree, get a fellowship, and then get a placement and then take responsibility for something.
That would make me a leader. It is one path.
On the other extreme, I could take responsibility for something today that needs responsibility taken, and then take responsibility for getting better at it. Even something really small. Then I could do the same thing tomorrow, the next day, and the next day.
That would make me a leader today, and an even better leader tomorrow. That just puts me on the hook today, instead of 5 or 10 years from now.
Title or not, we’re not leaders until we take responsibility for something that needs responsibility taken. The second we take responsibility, we instantly become a leader.