Asking for more hours

I have been working at a new culver's location for around 2 months. I am a minor, so I have restricted hours but, I am available all day during school hours. I have been noticing a decreasing number of hours I have been scheduled weekly. I don't think this is because of bad performance, because I have gotten compliment's a bit based on my work. Should I talk to my manager about my lack of scheduled work, or do you have any advice for me?

Thanks for the help!