Apologies for forum-crashing
AEPhi's rule is that no one except initiated sisters may wear the Greek letters - whether sewn-on, screenprinted, embroidered, whatever. Others (including new members) can wear "AEPhi" or "Alpha Epsilon Phi" written out.
I personally don't feel you should be wearing sewn-on letters of a GLO unless you are either an initiated member, new member (if your org allows it), or a sweetheart (again, if the org allows it). Certainly someone's little sister who's still in high school shouldn't be running around in them.