A girl ignored my text?

(I posted this a minute ago but with a less snappy title so didn't get many replies!)

I met a girl at a job interview (we were both going for the same job but neither of us really wanted it - or got it!). We spoke for a while and made each other laugh, afterwards I was walking through town and bumped into her again I offered to take her for a coffee but she said she has an essay to do (she was talking to me about it earlier) so I said maybe we could go after she hands it in "to celebrate". She said she'd "think about it" so I asked her for her number. I got it and then later on I sent her a text saying "this is my number, good luck with the essay" etc. It wasn't the kind of text that really needs a reply but she didn't reply at all.

She didn't seem like the kind of girl who'd ignore someone but do you think she gave me her number just to get rid of me? It happens to me quite a lot.

Should I bother ringing her for that coffee or do you reckon if there was any chance then she would have replied just to say hello and that she got the text?