Can anyone relate?

I have a 5 year old brother who I took care of since day one(I’m 24) so since she didn’t take care of him I don’t find her responsible to babysit my daughter. She also gives her things I don’t want her to have like soda, candy ect (she’s 7 months old) and gets mad when I yell at her when I tell her not to. She also gets mad when I won’t let her babysit. Idk how I can trust someone who won’t even take care of her own son or other kids and won’t respect how I want to parent my daughter. Anyone else have this problem? I’m also a stay at home mom so I really have no use for a babysitter.