If she is your close friend I would just talk to her about it and express your concerns. It may be that you have very similar taste, or it may be that after she looked at your book she racked her brain but everything she thought of she didnt like as much as what you'd written down...maybe she didnt think you'd care...there are a plethera of "what ifs" here and I know if it was me and this were my close friend, I'd tell her I was worried about our weddings looking the same and ask for her help in making sure that even if they're similar, they're not identical. Since they were your ideas to begin with, I'd like to think she'd be willing to compromise!!
Good Luck!
XOXO