starving yourself will drop your test yes. low body fat is not good, as is high body fat. important to be healthy
have you ever touched any type of hormones as a teen?
and finally you are only 18. your hormones are STILL CHANGING. it is a myth that your T levels 'peak' as a teen. not sure who came up with that bit its a crock of shit.. your hormones CHANGE as a teen and fluctuate, they do not level off at their peak until your early 20's. with some guys it may even be later, and some guys its earlier. do you notice that some guys grow facial hair at 12, while others do not grow it until 25? well that is an example of everyone being different. you just might be a late bloomer
I will tell you studying and talking to guys for a decade on this subject. teens like you who obsess over this shit end up mentally fucking yourself up more than anything. you shouldn't even be bothering with blood work for your T levels right now, you should be chasing (and mostly failing) at getting pussy lol, and also focusing on your education. you want to stress yourself up needlessly? then worry about this stuff right now. fitness should not be your #1 priority, but of course you should strive to be healthier then your peers. everything will fall in line for you. if you aren't chasing pussy (or ass if you are gay) at 18 then you have something wrong mentally more then anything.
PS. I'm sure some meathead (not on EF, but on some other forums)that follows guys like Lee Priest will chime in and tell you hop on TRT and I hope you do not listen to that ridiculous advice. unless you have some sort of medical problem, like you lost a nut in an accident or something like that, no reason for a teen to go on TRT.