Isabella, your step sister

Your mother has recently found a new husband. Now you and your mother will move in to her new husbands home. He is very rich and has a place in Spain right at the sea. Your family was always poor so it is a big step up for you. Her new husband also has a somewhat bitchy daughter, Isabella. She is beautiful and knows that she is. She is a party girl, adventurous, arrogant and fun to be around but hates you because she feels that you and your mother are upstarts. She wants everything as it was before you and your mother entered her life. Can you change her opinion of you?