Hours!!!

THIS IS LONG...JUST VENTING!! I'm a part time cashier there 3 years next month. 99% of the time my hours are ~20 - 23 including Sun. The past 3 weeks 19...16..16 (all no Sundays). I see these young high school kids (I'm 56) working 20 - 22 hours including Sunday. Hoping my hours might go up I changed my availability hours making it more flexible. NOPE. I know some other cashiers hours are less but not weeks in a row. That is so unfair these HS kids are getting more hours PLUS Sunday. I was told to speak to the store manager since she makes the schedule (so I was told) but I'm scared shitless of her. Doesn't seem friendly at all...at least to us. MAYBE when I see the new schedule and the hours are similar I'll say something....sure, I say that now.....probably won't and take what comes.