New job! Do I look “bad”/unprofessional” not responding

I recently got my cna & got a job pretty quick! I’m a single mom of 2 & accepted a part time position in assisted living so everything’s been going great but they are currently struggling with staffing etc so the lady that does the scheduling is constantly asking me if I can pick up shifts & I have but only mornings!But I just can’t work evenings/nights because I have no babysitters, I’ve tried explaining this to her & she will still beg/text me to pick up… I feel bad but honestly I stopped responding does this make me look bad??