I am aware of the idea that creasing your forehead will show you exactly where your hairline was when you were younger, but I am sure this isn’t the case for me. I am 18 and have some recession which seems to be stable (maybe a mature hairline) and may have been there way before male pattern balding can even begin to manifest itself. When I crease my forehead, the highest crease falls two inches below my hairline, but looking pictures from my 11th birthday, my hairline, at least the centre, definitely was not noticeably lower than it is now. Is there any chance this theory is not entirely true for everybody?
The top most wrinkle crease we talk about is just a rule of thumb that generally holds true on most men. Without seeing your 11 year old hairline with a wrinkled brow, one can not be sure of anatomical points of reference. Of course, not everybody is the same. Some people naturally have a very high hairline or a very low hairline.
We are all special, each and every one of us!