How hard is it to drop my 5K time from 18:26 to 17:30?

If you can run around a 4:55 mile then it should be fairly easy in my opinion if you have the endurance to get under 18. I run around a 5:15 mile and run 19:00 easy this year so you can do the math and 20 second faster mile x 3 miles = 1 min so 18 easy so maybe 17:30? Get in shape by doing lots of distance and 3 days a week core and rest