I don't know if your losing your hair based on your crown or not and it's the best you see a doctor who is a dermatologist, not a general doctor who knows nothing about hair loss. Where are you from? I read one of your other posts and you should see only a DERMATOLOGIST, other doctors don't know what they are talking about and you'll just be wasting your time.
Losing hair is normal and it's not a sign for balding. The sign for balding is when you lose hair and begin to see bald spots forming on your scalp. So maybe your hair loss is normal and your crown was always like that, it's the best to ask people who know you your entire life (parents) and also keep your eye at it and see if it's also getting thinner around that spot.
If it would get worse I still wouldn't say you should start using Finasteride but maybe Minoxidil could fill your vertex and then you could use finasteride in the future if it gets worse.
I also have a crown that is similar to yours, but also the hair around my spot is a little thinner. I went to three doctors, one recommended me on Propecia without even looking at it and even that I'm not losing hair at the moment. The other send me to blood tests and told me that it might be the Iron and Folic Acid shortage in my blood and the third doctor also said to finish the Iron and Folic Acid pills and give it a chance. So I'm taking those pills now and will giving it some time to solve itself and if it won't then I'll accept it's male pattern baldness and will start treating it very soon.
Take a blood test, see if everything is alright and if it's not then make it alright and meantime see how your crown is progressing and if it goes thinner and your blood tests are good then it's probably male pattern baldness.
Does your hair above your temples is thinning? If not it could be just a mature hair line.