Pretty good for your first time, but here are my thoughts.
The anisotropic metal texture is a good start, but it needs more detail. Generate some fractal noise ("clouds" in Photoshop, I think), squeeze it down on one axis, then warp to be circular, then multiply/screen it over your image. Alternatively, google around for a texture that you can screen/multiply over your graphic. Look at
for reference. Notice the graininess of the texture.
Secondly, I don't like the black on the bottom. Too distracting. Tone that down by either making it lighter, or not as large. Maybe you were trying to create depth with that, but it shouldn't be that dark, so brighten it up a bit. Tone down the inner shadow's opacity on the letter too. This is just a small detail, but maybe add some grey shapes on the bottom edges of the letters to make it look like I can see the sides of the metal where the letter is cut out.
Third, I don't care for your font choice. It's not bold enough to draw my eye immediately. Try something thicker with more rounded corners.
Lastly, why is the metal texture still visible in the teal letter? Is there another layer of metal below the one that's cut away? If so, it should be offset a bit to account for that. It detracts from the illusion of depth that you're trying to create as it is.
It's a great start, and it's impressive that you were able to do this unaided, but could use some work.
Keep applying yourself this way in all of the software that you want to learn, and you'll learn very quickly.