My father passed away four months ago of a ruptured abdominal aortic aneurysm, I was traumatized, I'm 20, what are the chances of me developing this?

Most of these. Abdominal aortic aneurysms (aaa's) occur in older (over 65) patients with a history of smoking and/or hypertension. If a AAA occurs in someone younger or without typical risk factors then testing for various syndromes and genetic predispositions can be performed. Your doctor can help parse this out.
AAA killed DAD. 23 F My father passed away four months ago of a ruptured abdominal aortic aneurysm, i was traumatized, , what are the chances of me developing this? ANS: unless your family has a strong Hx of AAA not very likely. So do family tree and AAA. Much less common in women. Esp if you do not smoke or have HTN.