Looking to Finance a car with limited credit history?

Im 21 years old. I have had credit for about 11months. I use it alot and always pay early and have never went over my limit. Right now I work full time and make about 1184 a month. I have no bills or anything like that. I wanted to put 3grand down on a 07-08 mustang gt. My g.fs sister only has 2months credit history and got approved without a cosigner on a 14grand car... So im kinda hoping I can do this?