Male pattern baldness or mature hairline?

[Mortimerr2015]

This is my first post and I know I should get professional examination as well at a dermatologist but I'm 20 years old and I noticed my hairline does look a little receeding in my opinion but I'm not sure. I've had longer hair with bangs by past my shoulders or anything but long enough to cover my biggish forehead basically all my life. My bangs were cut shorter than I wanted a month or so ago and this is when I notified. I've provided some pictures I'm just curious if this is a receeding hairline caused by mpb a maturing hairline or if this is normal for my age and just looks this way because of my bigger forehead. Thanks for your info!

http://postimg.org/gallery/2n3xl8yna/