Great first build! It looks like you used regular paper. The fiberglass resin will weigh it down so much that it will turn to mush. Don't throw it away, you can reinforce it with card and keep going. The fallout helmets look beat up anyway, just call it "battle damage". Lots of people have had great results incorporating flaws in the build into the weathering. There are some great tutorial videos in the stickies too, so you get a better idea of how it all comes together.
For all other noobs: The term "noob" is not a derogatory term here. It has nothing to do with the quality of work that a new member puts out. It only states that the member is new to the forums. We were all noobs once, but read all the stickies (they are marked with "Sticky" and are the first topics in each section) and show us your builds then see how fast your noob status disappears.