Is it possible to switch from French and Econ to straight Econ

I am an international student and i got an offer to study French and Economics at Warwick for this September. However, after doing some research I found out an economics joint-degree doesn't come close to the depth of a straight Econ degree and is kind of disregarded for prestigious masters degree later on. Im also not very keen on 4 years because it would mean having to pay one more year with international fees. French and Economics requirement was AAB, Econ is A*AA. I achieved A*AB with A* in maths. Do I have a chance? Do I need to ask now or is it still possible to switch at the end of first year?