Is this male pattern baldness thinning or chronic telogen effluvium? No family history MPB. I'm 21 YO. (photos)

I would need your whole story and to see your scalp up close to really give a complete evaluation. However, that said - CTE is rare in a 21 yo male and your photos certainly do show a patterned type of hair loss. 

Your biggest enemy is the progressive
thinning leading to a balding pattern that is not evident at this point in
time. The degree of thinning that you are experiencing would suggest that
you should see a doctor who has a HAIRCHECK instrument and will most likely will get
Bulk Measurements of your hair to determine the degree of the thinning
that you are presently having. If the diagnosis is early genetic hair loss
(the most common cause of hair loss in young men), then the best treatment
would be the drug finasteride which is highly effective in men of your age
and may not only stop the hair loss but possibly reverse it. If you are
developing a more advanced balding pattern the best test to get
will determine the Bulk Measurements of your hair and this will show, over
a one-year time frame, how effective the treatment will be. Once you know
this information, then you and your doctor need to develop a MASTER PLAN
which will define what you need to do over the years to come.