I'm 39 years old. Although I was a hobby/treadmill jogger and even ran some marathons in my 20s (PR 4:22 on my fourth try), this summer I started running seriously. I raced a 20:29 5K and a 3:40 marathon. My best mile workout time is 5:54. I'm 5-9, 157.
The question: If I train like a beast the next five years, what can I peak at in the 5K?