AITA for saying to my 18 yo friend to take studying more seriously?

We are both 18 I got into a state college she wanted to come too but unfortunately she didn’t pass the exam(matura) and had to wait for the second term.she didn’t pass pass this time but the law college didnt accept any more students
So she took economics she had today the exam for acceptance
She tells me she didn’t know what to do some questions she just guessed
She works also in market but isn’t really study smart nor street today she had called me to show which way is the college.
I told her she should take it more seriously and not complain that economics isn’t what she wanted to study.
She tells me not to intervene in her choices getting mad that I got mad about her non serious behavior towards it
My sister tells me that in college I should try to make more friends with same school capability as me because dealing with some girls like this can be exhausting
(I’m not saying she’s a bad friend but sometimes she drives me mad with her lack of knowledge)