So...I'm writing a romance and basically, it's Summer-time and the protagonist visits a tiny village in the Scottish Highlands and while there, falls in love before returning to London for a major operation where things go drastically wrong. The main themes of the book are; summer romance, young love, loss and friendship. The summer romance is important but I don't know how long to take before introducing the person she'll fall in love with. Is there a rule for this? I know that in a lot of books, people prefer to introduce the main character in her normal environment before something happens to change the story. When do you think I should bring this change into effect without making the beginning boring?