Thoughts on graduating a semester late to pursue a career in IB

There have been threads on this, but not any recent ones. I'm a rising junior at a semi-target with a 3.6 interested in IB. The problem is I didn't know I was interested in IB until recently, so though while I do have internship experience (just start a PE internship), I haven't networked at all or applied anywhere. I was thinking of graduating a semester late to be an SA after my first semester of "senior" year.

Pros: Along with allowing to be an SA, this would allow me to raise my GPA, and more importantly add a music major, which I legitimately want to do. Cons: It would be extremely expensive, and there is no guarantee of getting an offer as a SA, or a return offer if I manage to get an SA offer.

I would like to hear what the general consensus on graduating a semester late is in, and I would like to hear from those of you who have done this.