as you are already 16, I can assume that you are very intelligent, so I am going to write to you the same I would have written to any adult person posting on those forums.
Use google.com or bing.com to search for any word you do not understand. I am not going to try to explain every single word. If I use expression "TMAU", if you don't understand what it is , google it.
First, you have to understand that you may have a health problem.
Your problem may not be something easy to diagnose or treat by an average medical doctor, so you will have to start studying medicine and health yourself, and try to help yourself.
No, you do not have to learn everything about all possible diseases and all possible medications, all you have to learn is what is causing your particular problem, and how to manage your own health, and by managing your health, how to manage your own smell.
People generally smell because of 3 main reasons:
#1 Something is wrong with their digestive tract
#2 Genetic defect, like TMAU for example
#3 some combination of #1 and #2
As you can see, I have not mentioned taking shower, cause until people reach this forum, personal hygiene is something they already do several times a day.
What can be wrong with the digestive tract?
If you have ever taken Antibiotics , Antibiotics can kill good intestinal bacteria, yeast and virus, opening the door for bad bacteria, bad yeast and bad virus.
Once bad bacteria, bad yeast and bad virus overtake the digestive tract, they cause further liver damage, kidney damage, poor digestion and generally poor health.
Health problems that may arise after repeated use of Antibiotics and that may cause even more problems are: