Kind of tough to predict. My questions would be:
What was your PR in the 5k previous to 17:00?
How consistent has your mileage been this summer?
Are you doing primarily easy miles with some tempo runs or running hard every day?
How long have you been running cross country?
What PR's do you have at other distances?
Does your coach know what he is doing?
Every runner is different. For instance, My first year doing cross country was my junior year, I ran a 17:13 in July before the season started and ended up running a 16:30 4 weeks before the state meet (our coach was awesome). I primarily did 7:50-8:30 miles 6-7 days a week and would usually be around 35-40mpw. However, I did run a 206 800m, 445 1600m and 1041 3200m the prior track season, I knew I had some natural speed, so I primarily focused on building my aerobic base while avoiding injury (I am very injury prone).
I hope that gives you a reference point, I would imagine you could go 16:30 at the minimum using myself as a reference. However, I think you will go much faster than that if you have been training correctly. Stay healthy and train smart, you potentially have an excellent season in store!
i was hoping for that, ive been consistently building up over the summer and intend to hit 60 next week, most of that milage is in the 7-7:45 range with one tempo a week, my mile is 4:52, and a two mile 10:13