The Asian Commercial Sex Scene - Fiona, my stepsister

Hi Bros, my first attempt with a story, so please support and advise! thx

Lets start with some background info. I'm 18, studying in an average JC. Average looks, around 175cm in height, loves racquet sports. My Dad is a successful businessman, so I would consider myself quite well to do. Mum helps out at the company. As the only child in the family, I was always alone at home since young. Hence, I have always longed for a sibling to play with and to take care of me. Little did I know that my wish came true on my 18th birthday...

Eventhough it was a Saturday, my mum had to go back to the office to handle some work. That left me and my dad and he decided to bring me out for breakfast at our favourite restaurant. He seemed different that day, always wearing a smile and seemingly excited. .'Perhaps he had a surprise in stall for me?' I thought to myself, getting excited too. We settled in at the restaurant and ordered some food. It was then when I noticed a sweet looking girl walk through the door. I was immediately drawn to her. Decked in a white sleeveless top, she seemed to be exuding a special aura. I estimated that her height was about 165+cm and her tight black skirt displayed her long slender legs. I was so engrossed with this chio bu I almost failed to notice my dad waving to her. Before I knew it, she was sitted right opposite me! Sounding rather nervous for a man who has clinched multiple massive deals in the corporate world, my father introduced her to me. Dad : 'This is Fiona, your stepsister.'
Wait, what! Stepsister? My head was filled with questions I found myself stumped with. Of course, my dad had expected all these and was ready to explain. Apparently, a few years before I was born, my dad had a tryst outside. Fiona, the result of the tryst was kept a secret from everyone else, and she spent 21years on her own until now. She went into the corporate world after poly and is now holding an administrative job. My dad still keeps in contact and provides for her though.
Dad : Now that you are 18 years old, I believe you are mature enough to handle the truth. I hope that you two will look out for each other and take care of each other in the future.
Well actually, I was not exactly sure what to think. On one hand, I'm furious that my dad has a illegitimate daughter. At the same time, I have always dreamed of having a sibling in my life. Now, I have an elder sister 3 years my senior. A hot elder sister