I am an only child and so is one of my female friends. Our families do everything together. She's like a sister to me because we are so close. I think both of us have feelings for each other but are worried about ruining our friendship. How do we handle that?
The most solid romantic relationships often start with being really good friends first. If your friendship is that strong, it will only enhance your relationship. Relax and enjoy. If it's to be, you'll know soon enough.