la niña
Your sister or some stuck-up relative who thinks she's the best thing since sliced bread and can't stop talking about how amazing her life is. Most of the time, she's just a spoiled brat who got everything handed to her.
My sister brags about her new car like it's the only thing that matters in life. She didn't even win the lottery.
My cousin posts 10 selfies a day and still thinks she's the main event.
My aunt talks about her vacation like she's the only one who's ever been somewhere.