Advice No.2

When I told my mom I wanted to live here my mom said to not complain when we got here I said that I wouldn't and really thought there wouldn't be anything here to complain about but now I found something I think i should talk to her about but I'm not for sure. We moved in with my cousin who is 27. She has a daughter that is 4. My cousin gives her what ever she wants sooner or later. Her daughter will say I want this or I'm doing this and my cousin will say no your going to stay here or your going to bed. Her daughter will start screaming bloody murder and then her mom will gave in and give in and let her do it. She never follows through with anything she says or does. I baby sat her daughter yesterday and she woke up screaming for her mom, so I went up stairs and told her, her mom was at work well that wasn't the best thing to do, she started crying again. She had been playing in the water at her school and had these wet clothes on so I said let me put some dry clothes on you she screamed rite in my face. By then i had, had it with her so I left her in her room until she stoped crying. When she finally stoped i asked if she wanted a snack or if she wanted to go to the park, but again she started screaming at me again.
I don't know what I should do. I promised my mom I wouldn't complain once I was out here but now I really thing I should let her know she is bugging me.
I am confused if I should tell my mom or not. My mom does not have a job rite now but she cleans houses with my other cousin and gets paid a little bit. I don't want her to think I'm going to complain about wherever we live because I'm not I just want to go home and relax not listen to a kid screaming all night for the stupidest reasons. If you think I should talk to her about what do you think I should say?