She is the oldest of three sisters and was known as the geeky sister.
That Book has been Guessed by Kristin. It is indeed Getting What You Want by Kathy Love.
I adored this book when I read it and gave it 5 stars. Sadly the next two weren’t as good – for me anyway – and she has since written funny vampire books – which I don’t read. So for me this author full of promise, and maybe she still has it, was a one book wonder, until she switches genres anyway and writes another book as delightful as Getting What You Want – a don’t miss book.