How long does it take for an AAA to develop?

I've had gallbladder problems over the past few years, and I'm just trying to be positive that my current symptoms are from that and aren't indicative of something else.  Lately, I've noticed my stomach pulsating when lying down and leaning back (but I'm not thin, so can this be normal?) and had some stomach and leg pain.  I'm only in my 20s, but I do have a family history of AAAs (although they were both in smokers, which I'm not).

My question is: I had an abdominal UltraSound and full CT just 8 months ago for the gallbladder -- all perfect. These obviously would have shown an AAA, so there's no chance one could have developed in that small span of time, correct?  I have considerable anxiety, so I'm just looking to put my mind at ease.

[skydnsr]

Don't know how long it takes for an AAA to develop, but you could get the radiology report from eight months ago and see for yourself exactly what it says.  I know that with thoracic  aortic aneurysms, sometimes patients get told that their scan results were "normal," even though the radiologist's report might have made note of a dilatation.  (This happened to me, among others.)  The referring doctor considered the dilatation nonsigificant, so he never mentioned it to the patient.  

If your aorta was truly a normal diameter all along its length only eight months ago, I would be shocked if a young person like yourself could have developed an aneurysm in that length of time.  But you need expert consultation.  Looking at the actual radiology report and then talking more with your primary doctor is all I know to advise you to do.  

I have seen posts from other people on this forum who were scared by having visible or palpable pulses in their abdomens and it turned out that they did NOT have an AAA.  But with your family history, it is good to play it safe and put your mind at rest.