I check based on performance against more Gif-like ships. Especially against ships I got in. I would never make a teacher enter based on being able to beat built-in ships.
Your ship is okay, but not good enough for you to be a teacher. Perhaps if you have a more competitive design I can let you in, but based on this I will sadly need to say no.
(I should make a note that you can still become a teacher if rejected, as long as your new ship is good enough.)