"Hey, wanna go on a comic book store date with me at [store name] on [day of the week]?
The ask, the expectation of a date (and admission of romantic interest), and a specific time and place. Don’t leave the question open-ended or vague. Then she can respond in a few ways: 1. Yes. 2. I’m not free that day; is there another day that we could go? 3. No thank you.
This makes everything as clear as it can be, with little room for misunderstanding. And it’s not a dumb idea at all to have a comic book store date. If you have a hard time talking to girls, don’t talk to girls. Talk to humans who happen to be girls. They’re people, and you’re a person too, so you don’t need to overthink it.