UCLA pre-med/bio... How hard is it really?

I know the bio majors/pre-med has a reputation for being super hard and cutthroat and terrifying. Alas I wanted to try my luck and managed to get into UCLA. I grew up in a high school with many over achievers and it fostered a connection among the AP students but not competition. We were all smart but also collaborative. Everyone was helpful, if you asked for notes/tips/tutoring, someone would. In the end, we all managed to get into amazing top tier schools. We have kids attending PENN, MIT, and even Stanford. Over 20 kids also got into UCLA. But is that something I will see at UCLA?

How prepared should I be for the competitiveness? Should I be super wary?

Are there a lot of gunners that will try to bring you down?

Is there a bell curve at UCLA?

For current/past UCLA students that majored in this area…what are your tips to being successful?

Thank you, any and all replies are greatly appreciated