Travelling with my stepmom

Dad's planning for a family vacation next month, that means travelling with my stepmom. For the past weeks since she transferred at our home I can say she's fine, trying to be the best wife for my dad. She's actually from China, my dad met her at a new years party dating service in Shenzhen last year. They've been dating for months and decided to get married, the rest is history. Well, to be honest, I'm still not comfortable with her, part of me wants to accept her but for some reasons I just can't! Now, I'll be spending my vacation with her, what should I act for the whole duration of our travel? I need help guys!