Your images are not like my avatar. And just for info, my avatar was shot by a student (like myself) who had been using his camera for 6 months.
Your image is not cropped the same, there is way more stuff going on, the exposure on the bright side of the face is darker, you have a helluva lot more blacks that are totaly blocked than I do (mine were mostly at the bottom and not too much, yours look like half the frame), the pose is not the same. Mine is more basic, I'm not pulling a Mike Tyson.
Plenty of people gave info, but you focused on whatever was positive. Wrong mind set to learn IMO.
If your exposures look fine on your screen, check your screen. Maybe the brightness is turned up. And look into a monitor calibrator.
Some of the best comments I have received is people telling me my images suck. Some of the worse comments I have received are simply people who drive by and post "nice shot"
Badly exposed, the pose is just off, the light is awkward and the background is way busy.
Try keeping things simple at first.. simple clean light, standard pose, get a bit higher than him, get closer in, nice and sharp eyes.
Once you can nail those basics, then move to some funk
I guess this wasn't helpful. Do I need to draw you a picture?
Your age has nothing at all to do with it. I had no idea you were 18 nor do I care. People like to throw their young age in there when they have a lack of experience and knowledge, but yet when other people bring up the same issue, they get ticked. Not you specifically, I'm just saying.
You should define feedback you want to receive and learn to properly take it, digest it and learn from it.