Rescheduling a first date?

I matched with this girl last Friday night who I am really into, exchanged messages saturday-sunday and sunday evening i got her number. I am busy mon-wednesday so is she, so i set up a coffee date for this thursday (tomorrow) after i get off work. this was before i got into work monday when I found out we all have to do a mandatory 10-12 hours for this whole week.

I am dead tired at the end of my work day, so I am a bit concerned about tomorrow as I also have to wake up at 5am the next morning. I am going to be way busy this weekend as well, so I cant meet up with her until next week if I do cancel tomorrow. I have never been on an online date before, so I dont want her to think i am flaking out on her and not interested, or having her lose interest in me since there are plenty of other guys out there who have better schedules then me. Should i just go for it tomorrow even though I going to be way tired or would pushing this to next week not be a bad thing if i explain my schedule to her?