Practice date with my sister?

I'm a 21 year old guy who has never been on a date with a girl. I'm not the most attractive guy but I'm a 10/10 on the inside. My friend from college asked me to take out her visiting cousin to dinner and a baseball game since she loves baseball as do I. Since I have no dating experience, I'm really nervous. My sister is gorgeous and goes out with a different guy every night. She has tons of dating experience. I'm thinking I should have a mock date with my sister so she could give me pointers. Would it be weird if I asked my 19 year old sister out on a practice date?

Practice date with my sister?
Post Opinion