Initials shapes were created with the elipse tool, the star tool. and using the pathfinder tool i gave the desired look everybody knows Captain Americas shield looks like. 

The texture was a free download. If you google it, you'll get suitable textures to free download and meet your needs. 
This was finalized in photoshop as usual to give it the grungy worn away look as i have applied the texture and changed the blending mode of the the texture and reduced its opacity.

And the result was beautiful to the eye!!