need ur opinion ASAP

so... i have this cousin, she's about 7 and she's just a total bitch. i literally can't fucking stand her. but ofc i dont tell anyone that. my mom and dad are separated and she's my cousin on my dad's side/ i go there every weekend. the issue is that she's been a real bitch about my food the last few months. i work now so i have enough money to buy me trendy drinks every time like boba, some frappe etc., i sometimes buy myself a little snack too like fries or sandwiches or just simple street foods. and i'm very introvert so i like eating it at home (my dad's which lucky me, my sis and i have our own room) where there's no one to bother me. the thing is, she's being all puppy eyes on me., asking for my food(it doesn't really work on me bcs she grew with me babysitting her so i know that she just wants it bcs im eating it.) every fucking time. ofc, being the bigger person that i am (like what my mother taught me) i always give her a couple of sips and a few pieces from my foods and drinks. it really annoyed me bcs she just won't stop until i give her the whole thing (fyi. i did a few times) and i don't really like that. the one thing i hate the most in this world is people begging me for something and making me look like a selfish bitch when, really, im more than willing to give them what they're asking for.(im not a very selfish person imo). and it really annoyed me how she's begging like they're starving her but they have this pantry that just have expensive products that is free for them to eat anytime. it happened for a few times now and i kept quiet since she's a kid (maybe a devil in disquise idk) and i thought that maybe she really want the food since they don't really eat out a lot or she just missed me and was asking for my attention subconsciously. but it fucking annoyed me that when we were in a party and i went home with gulp, she was literally asking for it. as in she was asking for it like "Please give it to me rn" i wasn't giving her my drink since i really like it but i gave up eventually bcs all eyes was on me like I'm the villain of the century. and the night moved on blah blah. when we were alone with my family, i told her that she shouldn't do that bcs some people might get annoyed with the attitude. including me ofc. and like i told my grandmother about it. and told her to at least discipline her. like genuinely talking, I don't want my baby cousin to be seen as the girl who asks for people's food. and bruh. they literally told me to just let this slide since she's a kid and that im older and stuff. the kid had no money blah blah  SHE LITERALLY ASKS FOR 20 PESOS FROM U EVERY HOUR. ik it's not my cargo and stuff but i recently told my mom and she said that it's my fault for speaking up. fucking sick people.