MBA after undergrad?

For those who have been active on this thread, not sure if I am raising these questions on the right thread, If I am not, please direct me to the right place.

I am Freshman student at Fisher College of Business (Ohio State University).
Intended major / specialty = Economics
Working towards BSBA (Bachelors of Science in Business Administration).

  1. Should an undergraduate student pursue MBA right after graduation or go for a few years of work experience before going into MBA (I know the importance of this route, those who have work ex bring in more enriched experiences to the classroom discussions)?

  2. If it is not advisable for undergraduate student to pursue MBA right after graduation, then why would schools like Kelley offer 3+2 programs (joint programs)? Will these joint programs be effective? https://kelley.iu.edu/3_2MBA/Admissions/Tuition/page29977.html

Thank you all!