Most Helpful Guy
Showing yu texts from another guy is a sign she wants you to back away. Maybe not completely away, but for now she's not eager for any relationship with you. She might be OK with chatting in class or casually elsewhere.
She knows you've been flirting, or trying to flirt, and hasn't responded in any positive way.
If I were you, I'd try ignoring her a little, and see if she then wants to initiate contact herself.
If not, it's goodbyesville..