ok im 15 and my best 5k was 25:55 i really want to get sub 20 minute mile but for now im focusing on a sub 24. Heres my weeklying running plan: monday; 3 miles, Tuesday; Half of my long run, Wednesday; 2 miles (speed workout), Thursday; Half of my long run, Friday; 4 mile, Saturday; long run. Right now my long run is 6 miles and i go up a mile every month. Is this a good running plan?