I'm hoping to run a marathon in June next summer. I ran my first one last May in 3:29. I had limited training and didn't pace it well at all, with a 1:36 first half. Hopefully I've learned from that. I've also run 2 halves before that, a 1:34 and a 1:28:30. This year I want to break 3:00 in June. I was planning on loosely following one of the 24 week plans in Daniels' running formula since I have the book. Is sub 3, a 30 minute PR possible for me with better training and pacing?