I made a similar score (something in the 12-14 range) when I took AAMC 3 before I had started any studying. Ended up scoring a 32 on the real thing. Not the greatest score by SDN standards, but starting from where I did, I didn't really expect much better. A score as low as ours indicates that we've had a weak science background (for me, I was always focused on memorizing in my undergrad pre req courses rather than understanding). Or it could simply indicate that you haven't finished your pre reqs. Regardless, your initial score doesn't mean anything.