I'm 30 years old. Not a fabulous runner, never competed in high school or college, but I love it and do fine as local amateurs go. I'm around 70% age-graded performance at most distances. Hovering around 3-hour marathon, 5-minute mile, etc.
If I want to run in the 2020 Olympics: what event is most likely to get me there, how (and how much) do I have to train, and if I complete that training perfectly what are my chances?