Economics or Chemistry

Great question. My advice would be to take Econ. As Galen said, Economics is core to finance (many colleges without business schools don't even offer Finance as a major - the comparable major would be Econ).

Econ is a class that would be helpful regardless of what you choose to pursue - its theories spill over into every day life and I feel would be beneficial for anyone to take. I definitely wish that I had been offered the option to take Economics in Highschool!

I hope that was helpful and best of luck! It's great you already have a good idea of what you want to do, so you're definitely ahead of the game :)

I agree with the previous answers and believe that your strong math skills will be very valuable in both finance and architecture. I think Economics will be very valuable in both careers and life in general. If you get a good teacher it should be very interesting as well and economics is very complementary to finance. I hope you are also honing your writing skills as so many people that are strong on the numbers side are limited in their writing skills. And remember to have some fun!

As Mitchell mentioned above, Econ might be important for Finance but Math (and even Physics) which equip you with quantitative analysis skill will proven to be useful for both Finance and Architecture. A good combination of Econ/Finance knowledge and Math skill would have you prepared for most of the Finance professional positions, while Physics + Design are crucial for architectural work.

Dropping Chemistry would make most sense in this case.

Economics is core to finance.

Honestly, they're all great subjects that open a lot of doors, so if you have time, explore them all and see if any in particular really excite you.