@Thatperson,
"Hi ___, do you want to go out for a pizza/coffee/soda?"
Period. No feeling confessions are necessary. Just ask her out for a non-alcoholic, no-strings-attached time. When it's done, if you enjoyed yourself, say so, and then ask, "How about we make the next time a real date? What day is good for you?"
She can then either say yes and you arrange a date, or she can claim she thought you were just friends and it was a friendly soda or coffee or whatever.
You should not rush into big-time confessions of feelings with, well, anyone. And this also covers her. She can let you down a lot easier and she does not have to explain any feelings she may have about her sexuality as they are, unless you are in a relationship,
none of your business.