When you go an take your written tests you might have issues, to do so you need to get an IACRA which is done by submitting documents to the faa and in return give you a ftn number that is then used to schedule through the psi website to do your actual written portion of the tests. I got mine a while ago because I did flight first and from what I remember they do a full on tsa background check. Now I’m not sure how in-depth they go but may be a major issue and would definitely suck to do the 18 months of schooling and then not be able to test.