I am a 26 year old with Norwood grade 3 symptoms. I want to know how suitable my donor area is for FUE transplants? (Photo)

Photos cannot assess if you would be a "great" candidate for surgery.  Usually this involves seeing a doctor in person so they can understand your exact goals and expectations.Most men have good donor hair for a hair transplant surgery.

You have not a norwood type 3 loss...Receeding hairline is not a hair loss because of ongoing process of androgenetic alopecia but  a simple juvenile type maturing of frontal hair line.  That is seen almost every young boys almost between 16-21 that have a very rounded hairline without recession in the corners.  Recession in the corners is a sign of mature pattern male frontal hair line.So I dont recommend you to have hair transplantation .

one of the draw backs to FUE hairtransplant is donor depletion. From your photo your donor seems to be thin alreafy. You have to see a hair restoration specialist in person to get an evaluation. 

Your biggest enemy is the progressive thinning leading to a balding pattern that may not evident at this point in time. The degree of thinning that you are experiencing would suggest that you should see a doctor who 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.