A student may decide that they can be an instructor.
This sounds reasonable.
However, can a student assess this for themselves?
It is like a person deciding that they want to climb a mountain.
Have they researched the criteria?
Do they meet with the necessary fitness standards?
Is their skill level adequate?
Can they be trusted to do what they are required to do?
You may think that you are good enough...
You are not an instructor.
You have not climbed the mountain.
From your perspective you cannot even see how high the mountain is or understand what is involved.
Only the most arrogant person decides for themselves that they are instructor calibre.