Testosterone for penis size ?

hi i am 19 years old and have a 5 inch penis errect but its really thin i started pubitery when i was around 14 years old i now have full pubic hairs and under arm hair and voice broken and facial her is around 40% completation for stubble so maybe i am still in the process for my penis to grow in width and lengh but i have read reveiws 20 is the latest ever and your penis will not grow no more which i am 20 next month and i am really not happy with my penis size mainly on how thin it is will taking testostarone tablets help me before its too late and i finish pubity or can the docters help or is there anything i can take as i dont want it to get too late and have too live with a small thin penis as i am still a virgin for this matter thanks all help appreciated