Qualifications
It'd be nice if a bank would just hire any goofball with a calculator and smile, but, much like the loans they're going to want you to work with, they've got to be really careful about who they invest in. This means they're going to have to trust you with their money.
A bachelor's degree is almost a requirement in the loan world (source). If you've been working in a bank since you were old enough to count, you might still get the job, but you'll definitely be expected to know money management and be able to talk to people and not laugh at any of the more ridiculous loan requests.
The nice thing is you'll get a really great view of how the loan process works when you apply for your student loan. Just make sure you pay it back on time—the last person a bank wants to hire as a loan officer is someone who can't even pay back their own loans.
Besides education, there's that certain it factor you've got to have—well, it's actually more of an int. Integrity—that's the biggie. Ever been caught cheating? That's not going to fly when you're doling out thousands of dollars a day.
The numbers part of the gig is easy—if you've taken basic algebra, you can almost certainly do the math for this job. Integrity means you'll actually have to do what those numbers tell you, regardless of how it makes you feel.