Is it possible for me to obtain U.S citizenship?

[samkre]

Hello!

I am 19 years of age and I was born to a U.S citizen father in Sweden, my U.S citizen father does not have the required physical presence in the U.S for me to derive U.S citizenship from him(he moved to Sweden at the age of 3). I have done a lot of research in this matter and as it turns out you can obtain citizenship based on your U.S citizen grandparent's physical presence in the U.S if your U.S citizen parent does not meet the physical requirements, my grandfather on the other hand lived in the U.S for all of his life until he died 9 years ago.

So my question is if it's possible to file the N600K form after you turn eighteen?
I met all the requirements of the N600K form before I turned 18 so wouldn't I still be eligible to file for it in some way although I'm 19?

So if you have any knowledge or experience in this matter please feel free to reply!