Keep observing the situation, taking pictures in the same lighting/angles/etc., every month or so. If you see it worsening whatsoever, hop on finasteride. Earlier the better. You said balding runs in the family, and this is why vigilance is paramount.
At the moment, it looks like it could be the start of male pattern baldness, but it could also be your hair being like that naturally. I'm leaning towards male pattern baldness, but no worries as of now.
I don't want to fear monger, or urge you to get on medications needlessly, but when one can determine male pattern baldness is happening - waiting is not good either.
Therefore, keep taking pictures and observe the situation without panicing, whilst educating yourself on all potential treatments. IF things go south, you know what to do.
As of now, your hair looks good, but it's difficult to tell. Honestly, though, I'm about 90% sure it is the start of male pattern baldness. I hope I'm wrong though.