It looks great for a first render. Glad you still have your old files.
I still have a few saved up somewhere, but the really good ones were the ones that I have unfortunately lost, when a 2TB hard drive crashed two years ago.
And, I haven't modeled a guitar yet but I am about to do so for a character that I am going to sculpt in Blender.
I don't have the files. Unfortunately, i lost my old files due to ransomeware virus. But luckily i had the renders on a separate hard drive.
Will you post it here? If yes then excited to see it. ✌Thanks! @kryptik.tigrrr3d