Unless you’re a savant, your directing experience isn’t likely to get you a job as a director.1 It’s also unlikely to get you a production assistant job, either. If you put writer/director/producer on your PA resume, you’ll look like an idiot with delusions of grandeur.
I’ve been on some student films that were as big and professional as independent films. I’ve even seen students hire pros for key positions (which is basically cheating, in my book). If you worked on one of those, you probably learned a lot.
When you’re applying to be a PA on a big show, simply put “production assistant” with that student film and then… don’t mention that it’s a student film. Simple as that.
If you’re trying to climb the ladder on a low-budget feature, it’s okay to say you were the DP or editor or whatever on a student film. Just be sure, in this case, to clearly label that it’s a student film.
The line between “fudging” and “lying” is one everyone must draw for themselves, no matter how thinly. These are just my rules of thumb. Weigh in below if yours are different.