<human>: I've been wondering if wanting to run Leadville is a total pipe dream or something that is potentially realistic. 

Is a 100 miler something you decide you are ready for after having several marathons/ultras under your belt and you feel it's time for more? Or can a 100 miler be something else? 

Those of you who have run ultras at this distance, when did you know it was time and how far in advance did you decide you were ready? I feel like it's something that needs to be planned for two or more years in the future, but I also am prone to over-planning for stuff.

I have no concept of what 100 miles is like on foot in one session, but I really think it's something I want to do in like 2013/14. I talked to this lady who is in her 50s and has finished Leadville three times since 2005 and she was super inspirational and basically told me anyone can do an ultra, it's just a matter of how strong-willed you are because the mental aspect of 100 miles far outweighs the physical. 

I know all the stuff that you can read, like your long runs should be ridiculous and you should be well over 100 mpw, etc. I'm not really concerned about the training aspect because that's all easily available information. I'm looking for some insight from someone who was in this situation at one point in their life and decided it was time to run 100 miles and how they made the appropriate (or inappropriate) decisions.

Summarize the given text in a few sentences.
<bot>: How did you know you were ready for your first 100 miler and how long did you give yourself before the race?