Is it normal to be scared of this ?

My sister is doing a play with a guy she really likes. Tomorrow is they're last she they're having a cast party at the directors house tomorrow night. She wants to ask the guy to be her date but she's really scared. She doesn't even know him. She's only known him for a month. She said he's super cute. She said she stares at him all the time. Wether he's on stage or on his computer she said she could stare at him all night. She said he's so adorable. I don't know what she sees in him. She's not the only girl in the play who likes him. Her friends like him too. She told him already she likes him he smiled at her. She's afraid to tell him she has a crush on him. I met him last week he is really nice but I just don't get why they go crazy over him. She's obsessed with him. It's all she ever talks about. She even had written down in her phone her and his name over and over and she put little hearts beside them who even does that seriously. She's gone a little far with him she said she wants to have sex and she wants to have a baby with him when she's ready. She said when she's around him her stomach feels funny her knees week her heart beats really fast. She said she's never felt like this about anyone. She's even had dreams of her and him being married and having kids or dating. She even has names picked out for they're kids. She said he's the cutest guy ever. She really wants to ask him out but she's scared especailly since he's older than her. He's 30 she's 23. Is it normal for her to be scared ? How can she ask him ?