If there is a real possibility that you might apply to medical school in the future, then you should budget for a full 8 years of university where the last 4 years will be expensive. Even doctors do not make enough money to make it easy to pay off medical school debt.
Also, it is relatively common for people with a bachelorās degree in psychology to want to pursue some form of graduate school. While a PhD is usually funded, a masterās degree usually is not.
And if you are āeligible for some aidā then it sounds like paying $350,000 for a bachelorās degree plus another $450,000 for an MD might involve debt, and might involve a lot of debt.
What this means to me is that cost matters. You should run the NPCs, and see what each of the schools that you are considering is likely to cost. Saving money for medical school or for some other form of graduate school is a good plan.
However, there is also good news. There are a LOT of universities that are very good for psychology and that also are very good for premed. This includes most and more likely all of the Universities of California, and the CSUās, and you are in-state.
With regard to applying to Brown ED, the main thing that occurs to me is that you first need to figure out what it would cost (run the NPC). If it is going to be significantly more expensive than the UCās then I would be reluctant to apply ED. You might want to avoid ED, and get to compare offers from quite a few schools before you decide where to go.
Wherever you attend, your premed classes will be full of very strong students and will be very challenging. Exams will be tough. This will be true at Brown or WUSTL or Duke, but will also be true at UC Riverside or UC Merced or at one of the CSUs.
If you look at the students at pretty much any medical school, you will find that they got their bachelorās degrees at a very wide range of universities. A couple of years ago I got to listen in to the welcome reception for a highly ranked DVM program (veterinary medicine) and got to hear where each incoming student got their bachelorās degree. It was rare to hear the same school named twice.
Also, to me it does sound like you are doing very well. I do like your ECs. Make sure that you apply to at least two safeties, keep the budget in mind, and I think that you will continue to do well.