You can so anything you put your mind to. If you want something, you have to be willing to fight for it. Battle your own mind and the desire to give up. It's a never ending battle with giving up out there on the trails, and when you get past that and accomplish something like a run or a triathlon, you come out a stronger, different person knowing you can overcome your own mind. Remember your mind will quit before you do.
I'm starting to repeat myself, but I find it important to reassure you readers that you can do it, if you want to. You can do anything you want to do. And this can lead to bigger things out there in life.