Do I Have low testosterone I’m only 21 ?

Hi guys how likely it is for teenagers/ young adult to have low testosterone level I think I fall into this category even though I haven’t tested my T levels with the doctors because I feel embarrassed this are the symptoms listed below that I go through everyday life since hitting puberty 

-Low anger issues for as long as I Remember never got into fight and I don’t get angry

- always fatigue 

- can’t build any muscle even tho I went into  gym for over period of 9 months notice a sligh change 

- I have a slight enlarge men breast compare to others/ I also have fat on my body and I weight 70KG

- Low libido 

- and I don’t go after women like how my friends do because I don’t see no happiness in that 

I had few relationships before but I never used to get excited in bed never used to get erection and even tho if I was getting one used to be like 30% erect  and it always used to end with embarrassment can you guys help me please as I’m really embarrassed and I don’t know what to do thank you for reading serious answers please