<human>: Can you give me the gist of the text in a nutshell?

This afternoon I finished my first, of what I know will be many, Century Rides (100 km) on my bike. /r/GetMotivated had given me a lot of inspiration yesterday after work, which is one of the reasons I pushed myself when I went out today.

My [ride] was originally planned to be 70-75 km, however I was feeling good and decided to challenge myself to see if I could complete the Century Ride.

Some backstory: In November of 2012 I suffered a concussion, the 4th of my life, which caused me to completely shut down any physical exercise. Difficult because of my place on the varsity rowing team.

Since being cleared in April to return to sports I haven't had a lot of opportunity to get in exercise because of my summer job. I maybe had put in 200-250km total over about 3.5 months on my bike. My longest ride in the summer to date had been [60km] on Thursday (August 8th). Not all my rides are on that list, but everything else was around 20-30km each ride. 

One thing I reflected on after coming home was that you can do some amazing things when you challenge your mind and body at the same time. The hardest challenge is telling your mind "No I can do more" and pushing through fatigue.

I had set a goal of riding a century by the time I go back to school in two weeks. Looks like I underestimated myself because I set that goal yesterday (August 9) and completed it well ahead of schedule (August 10). 

Make goals and write them down, vocalize them, share them with other people but follow through don't just dream about them.
<bot>: Completed first 100km bike ride 13 days ahead of my set goal of doing it within 14 days from yesterday August 9th. Challenge yourself but specifically your mind, it will quit before your body.