Is this a reasonable request of I'm being asked to work extra hours last minute?

I am back in college again, and currently have four different babysitting jobs on the side. Two are consistent (same hours every Monday and Friday in the school year). The other is only in the summer or if the parents go on vacation. The other job though, has really inconsistent hours. She's got five people working for her, and a special needs child who is completely immobil and non verbal. I'm not really one to sit and do homework the whole shift. Sometimes a littlerto pass the time. But I feel like I should be doing interacting with her other kids, her child, and doing things around the house. But this month I've been ask to work four extra shifts last minute. I turned two down. But I have finally started saying if she needs me additional hours, I'm going to have to also work on homework... So tomorrow I'm now working 3.5 extra hours I plan to use at least that much time on school work. Honestly I try an plan my school work as much as possible around my schedule. But I know I can't put off my school responsibilities too.
Answers

Ranchmom1

It's reasonable to ask with a job of this nature. It's reasonable to say no if it doesn't work for you.

Anonymous

If you can't afford the time you say "I'm sorry, I'm not available at that time".

LizB

They can always ask, and you can always say no, or say that you can consider it in the future if they give you more lead time (say, a week) to check your schedule and get back to them.

Tri-Harder

If her son is non-verbal and immobile, that means you're saying you'll be a warm body in the house while he does nothing and has no stimulation for 3.5 hours. Just say you don't time. It is not reasonable to tell a parent you'll be focused on homework and not their immobile, non-verbal child.

mokrie

Any job can ask you to work overtime or extra shifts when they get stuck.