The fasted thing you can build is a hoop coop using cattle panels. Chickens need draft free ventilation in the cold so the moisture from them breathing and pooping can escape. A 8' x 8' would be a bit on the small size for 17 chickens better would be a 12' long x 8' wide hoop coop. If they are not free ranging you will need a 12' x 12' or bigger run. Subordinate chickens need space to get away from dominate chickens, things to run behind, room to get away. If not enough room then the pecking will escalate quickly.
Ventilation is important. Especially in winter. They will be fine in 3 deg. weather if they have good ventilation, bedding, and no drafts. Don't heat the coop, and they will grow nice down coats to cope with that winter weather. If you do heat, they don't acclimate properly, and then if your electricity goes out, you have cold, possibly dead chickens.
Enjoy your new hobby, and don't stress over it. Oh, and get out there and get bulding! They will need it sooner rather than later. Build at least twice as large as you think you need. (Recommended coop space is 4 sq. feet per bird, and run space 10 sq. feet. Make it bigger.)
Quick, cheap coop idea:
Go to Craigslist in your area and look up" shipping crates". often companies will sell super cheap or give away these huge wooden shipping crates. if you got a buddy with a pickup, go get some. use a couple attached together for your Coop.
No need to think you need to spend a fortune on this Coop and run .one of the most fun things about byc is to see how what a nice Coop you can make for very little money ,using your own ingenuity.