There are "Taught Correct" stances. In your case I would say whatever gives you the firmest most balanced comfortable stance. You want a stable platform for the upper body to do the work of aiming and responding to the recoil of what you are shooting. A stance that gives you an isosceles triangle with your arms is what is mostly taught which means the body should be square to the target. The Weaver stance is kind of what you are doing. The gun hand arm is streight and the suporting arm is slightly bent and you stand more at a right angle to your target. Look up both of them. Both work and you will need to adapt one or the other to your needs. Practice, good trigger control and consistant gun handling will do a good bit towards good groups also. There is a chart that will show you the leading cause of most shooting problems. I don't have a link to it. Maybe somebody will post it. Things like squeezing the gun tighter as you pull the trigger. Having your finger to deep or shallow on the trigger. Flinching, anticipating the recoil all have their effect on the bullet not going were you aimed it.
Ah ha I found it! Check this out: