Have her contact her teachers prior to school starting (such as when they are inservice), explain what's going on, and try to request missing assignments. The sooner the better -- that way she can "get ahead" prior to leaving for Barcelona. And I'm not sure about your state and attendance laws if in public school, but in some states you can withdraw her, state you are homeschooling her (just have to show a curriculum if asked, and there are many online programs), and then re-enroll her upon returning so that the absences don't count against her. Each state has a varying degree of homeschooling guidelines, with some being very easy. (I'm also a certified principal... but tutor kiddos in multiple states online. Some of my students are budding actresses who go to LA for pilot season each Spring and miss 10-12 weeks of school.) Yes, it's hard for students/teachers when one misses, but in the big picture, living life and building those family memories is so very important.