Work advice! Please help!

So I have my nursing assistant license but I just recently moved, and I have been struggling to find a job that is close to home with my license.

So I took a job at a gas station. I’m also going to school part time, have a son in kindergarten, and my husband works overnights 45 minutes away. Well when I took the job, they told me they would work around my sons school schedule (8:30-3:45) so I would be working 9am-3pm.

Now they have me going in at 4:30am and I just don’t have the child care for that. I don’t know how to tell my boss that I can’t do it especially since I told her it would be a struggle to figure out and she still has me working at 4:30am. I need to keep income coming in on my end so we don’t start struggling financially. I’m worried she will cut me down drastically on hours. What can I do here?