I can't tell really. You shouldn't worry about it unless you see old photos and the widow's peak you have has extended further.
A mature hairline is a receding hairline. And yes, nearly all causcasian men a develop receding hairline. It might stay like this for decades or even for life. You will never know. You should immediately jump on finasteride if you see further thinning. It won't regrow hair but this is the only thing that is proven to prevent further hair loss in most people.