I built my coop as a lean-to structure like a shed but raised off the ground a foot. If you can find a premade shed, that would help.I live near Los Angeles, so not many Amish here, but a farm store is a good idea. How did you build your coop? I'm not super handy but if there's an easy way you suggest that would be great!
You mentioned your school has a farm, does your school have a club or class that looks for projects to build? We have schools in Wisconsin that have classes were students build and create buildings to help students determine if they would like graduate High School and start a career in construction, electricity, etc. Maybe your school needs a project and they can build you a coop.
You can always learn how to build structures. I built my own after running ideas of how the coop should look with my dad. We only talked about the plans we never drew any out. Anyone can learn how to build a structure! I am a 30 year old woman and built my coop myself but I have also been helping my dad completely remodel houses, roofing, building sheds, etc. since I was 7.