Oxbridge or Top 15 US School.

Hi! I have quite an important life decision to make and would love to hear yall's honest opinions.

Background:

I am currently an international at a Top15 US School (semi-target though). Before coming to the US (last year), I had a conditionally offer at Oxbridge and bottled it big-time. I was lucky enough to have a great school as my "safety", so I instead  went there. Nevertheless, I was mad with myself and eventually re-applied to Oxbridge. After some time, I got an offer. Now I am in a really privileged position, where I can either stay at my current Uni, where I study MathEcon, or move to Oxbridge next year and study History (with a potential switch to Econ). I guess what I am asking is: your opinion on what would you do in my situation, based on career/work/academic knowledge. 

As for my career prospects - if that helps - I am trying to break into IB (especially if I stay in the US) or Trading, but I have always fought about staying in school and getting a masters/phd in Economics or History. Ohh, and I'm an international student from Europe, meaning if I switch its probably a good bye to the US for good. As for tuition, it's very similar at both schools, or in other words, crazy at both schools:/. 

Pros of moving, I currently think about: Sort of a dream school, Probably slightly better academics (although might be a marginal difference), Prestige.

Cons of moving, I currently think about: Moving to a new country (again), Starting a different degree and having the un-certainty of not knowing if I can switch to Economics, I really do love what I'm studying right now (in the sense of the course structure and the people around).

So, what would you do? Would you start anew at a (probably?) smaller job market, but a more prestigious university, or would you stay in the bigger market at a semi-target? 

Thanks a lot in advance!!