Am I the jerk for telling my stepdad and mom that they shouldn't be surprised that

when my little brother said to them when they pulled a prank on him, I'm a 20-year-old

female and I'm the older sister to my little biological brother who's a 17-year-old male.

He finished high school last year.

My little brother and I are really close.

He says I'm the best friend he has and he loves me more than anyone.

Of course this is not true, he has many friends of his own.

My brother has been asking our stepdad slash mother if he could get a new car for his

grad party since last year and he said he'd pay 50-75% of it with his own hard-earned

money while they pay the rest.

They said no.

I have a car but I've been working for one.

They helped me pay off for it.

So my brother's arguments with our parents got heated after a while.

One time I told my brother I'd help him pay off expenses for a good car once I got

my own.

He hugged me and said I didn't need to worry and that he owed me way more than I owed

him.

He continued to press our parents all of last year until eventually they gave in and said

yes like they did for me.

Note that our stepdad and my brother have a negative relationship for the most part.

Our biological mother and our stepdad got together soon after our biological dad and mom divorced

...