Shall I tranfer to another university for higher rankings?

Hi, I am a freshman and direct admit of Kelley School of Business. Having been here for three weeks, I found the school consisted of bad students and not competitive at all. I have passion in math and I want to pursue a double major in math, but the math rankings of IU sucks. I primary goal is to get in Investment Bankings. I got admitted to UIUC, U Wisconsin and U Minnesota before attending IUB. I wonder if it is better for me to transfer to another college? (Though Kelley has great reputation and high rankings)

No, it’s not. IU has a good reputation for Math at the undergraduate level and for IB Kelley is better than your other choices.
Are you in the Honors college? How many of your classes are Honors ?
Stay put, don’t underestimate the difficulty, make sure you rank high in eaxh class, get involved in the Honors college as well as other clubs, reach out to professors (go to office hours to ask questions to deepen knowledge of topics you found especially interesting, ask for further readings… )

You need to give it some time. Most of the classes you take freshman year are not particularly difficult as long as you go to class and study for exams. The bad students will get weeded out by the end of the year, and some even get weeded out after first semester. Focus on doing well and attend investment banking club meetings. Take intro to investment banking next semester or first semester next year, and try to get into the investment banking workshop.

I was somewhat annoyed by the bad students at first, but it’s not an issue after freshman year.

Expect your university to get more difficult. Keep ahead of your classes and be ready for when it does get harder (which can sort of sneak up on you). Also, the bad students will either get their act together, or disappear soon enough.

I’m with @MYOS1634 here. IU’s undergrad math is great, especially the honors program. If you’re still in calculus I or II, it’s not too late to switch into the S311/312 track to prepare for honors 400-level classes.
You should swing by the math club, too; some people I’ve met there are beyond talented, and every summer a few students do research at places like UChicago, Princeton, and CERN (to name a few).
The best thing about IU is that while it’s great at some things, it is in no way an ivory tower. Most kiddos who apply are accepted, and that is fine. Because of that, you’ll meet cool people here you’d otherwise never encounter.
Actually, please refrain from calling the student body ‘bad.’ I’m plenty competitive, and I’m proud to be at IU in any capacity.