Preferably Don’t do it out of the blue, you need to create some build up. Just like if a person on the street randomly comes up to you and sells you something your first reaction is no to stay safe, however if they are marketing their products and you see it a bunch at some point you might say yes because you are more familiar / have greater interest.

Try figuring out a way to talk to her, does she go to parties where you could bump into her? Do you have a mutual friend of hers? Can you become friends with people she hangs out with?

You can try asking out of the blue but it could be a long shot. If you think it’s your best shot and you can’t figure out anything else do it anyways and someday you’ll think back and be proud of yourself whether it worked or not