What's up with my hairline?

[willwork4pizza]

Sorry, another one of those "am I balding?" posts ahead. Edit: I'm 26.

My dad is mostly bald (he keeps it cut short, so it's hard to tell). But the men on my mom's side of the family seem to be keeping full heads of hair well into their older years. I know that means little to nothing, but I thought I'd share it.

I made a compilation of cropped photos of my hairline from over the last seven years (older ones are on the left, the two on the middle and bottom right are present):

http://imgur.com/a/cVol6

My paranoia may be getting the best of me, but I can't tell whether or not my hairline is receding, especially around the temples -- or if it's always been like that.

Are there preventative steps I should take, or just wait and see?

I appreciate any thoughts you may have (besides that I'm probably overthinking this).