Originally Posted by speedwobbles

19 with a sub 34 minute 10K? Even if you're new to cycling you're waaaayyyy more fit than a beginner and you're young too. I'm assuming you've got a pretty good idea of effort levels from running so just set out at an effort level you think you can sustain for however long you think you'll be riding. Heck, I bet you could go out and ride 100km without any real problems.