Accounting Major at Non-Target Looking to Break into IB

I am an accounting major at a non-target (UMass Amherst). I was duped into believing all of the hype about the big 4 and have secured three audit Internships for my junior year with PWC, EY, and Deloitte. However, after falling in love with my finance class this semester and doing my own research on sites like these, I would prefer a career in IB and the exit opportunities that come with it. I know this is very unlikely coming from the position I am in, but I would like to discuss what possible options I have.

I have developed into a decent student throughout my late years of high school but my 3.8 GPA and 1450 SAT were unable to get me into any targets. I chose UMass Amherst because of the in-state tuition and like I said previously was convinced of going into public accounting, without ever being presented with the idea of investment banking. I know my technical skills are lacking as I just took my first finance course and I realize it is probably too late to switch majors so I bought Simon Bellinga's textbook Financial Times (MIT Press) and have taken it upon myself to learn what is required of me. This is supplemented with excel work and general reading online through a variety of mediums.

I understand it is unlikely to break into this industry with this sort of background. The most unique thing about me is that I am a first-generation American and a first-generation college student, but I have to give it a shot.

I have read numerous posts but I am still unsure what is the better path for me.

Should I grind it out with networking and try and land an internship with a small boutique and make my way up?

or should I wait and pursue an MBA later on after starting my career at the Big 4 and then make a career change?

or do you have any other suggestions?

Thanks for any input.