How do I tell someone in church that is Goodly I dont wanna be their friend because they make me uncomfy?

theres a girl at church who makes me very nuncomfortable and scares me how do I tell her and her scary man I do not want to be her friend? Its like in worship I am very scared of her, especially during the part of service where people go and say hi to other people. So yeah how do I tell her? I would rather have her not FOLLOW ME EVERY SECOND of the day, and grope my arms. One of the Pastors said I could tell her but how?