Stop in for a cup of coffee

So, I'm working on a small cabin design, to put on my 10 acres. I need advice. Wife doesnt trust me building stuff, she wouldnt even let me build a storage shed. I have been given 30 sheets of metal roofing. all new, unused sheets. so I'm thinking of build a small get away cabin while we save to build the actual house. I'm thinking about 12 ft by 12 ft, 1.5 stories. I have enough metal to do this plus some new windows i got free as weel. just would need the lumber, and not all of it. So do I secretly build it and then surprise her, or try talking her into it....... :BangHead::BangHead::BangHead::BangHead::BangHead::BangHead:
Just do it....