Most Helpful Guy
My guess is that you're not texting her right. There are implicit "rules" to seduction through text. You need to be playful, yet let it shine through your messages that you're not just a friend... and showing decisiveness like appointing her to share coffee without asking her permission. No being clingy. No sending more than 2 texts in a row if you haven't received a reply from her.
Or maybe just give her a call, if you have her number (the texting dance is bull).