A girl in my Spanish class...

[Mous]

Do not do it in class, she will feel pressured and will say yes no matter what, than break your heart later. Just take your chance after school and ask her. Have a little chat before about something personal than just stop take a breath and look into her eyes, no were else and ask her nicely not desperately " will you go out with me"

^

This is more of something you would do if you've known her
for a good long while, and she already suspects you like her.

I'm telling you, OP, stick with seeing if she'll hang out with you alone,
first, on a few "mock dates". Don't SAY that to her.
Just try and see if you can get her to spend time with you alone,
rather than with friends etc. If she's smart (by any means) she'll pick up on this.