I am sure you will get approved if you have $20K+ down since you and your aunt never had any history with BMWFS or any high car loans. My credit score was 720 and I was on the same situation but I put a lot down so they approved me without any cosigner.
11 335is, KW1, M3 bits and what not
08 M3 Sedan 6mt, loaded, modded to the bone
Old: 04 M3 SMG