@le1997 I agree with @momcinco 's recommendation regarding breakdown of what kind of aid you are getting from each.
The following diversity statistics cut and pasted quickly from niche - you might want to check other sources as well. Both campuses appear fairly similar (27% non-white at Wash U vs. 31% non-white at Dartmouth and each having 8% International students of unknown race/ethnicity. 9% are undeclared for race/ethnicity at Wash U as opposed to 15% for Dartmouth). These figures don’t capture socioeconomic diversity, for which Wash U has been rightly criticized in the past and for which it is taking steps to remedy. The fact that Wash U initially offered you more aid that Dartmouth did seems like a good sign.
As for your lingering bad feelings regarding the John Ervin scholarship, I would try to let that go. If your COA is around 13K, it sounds like you got full tuition or close to it from Wash U. They probably make choices about distributing these extremely competitive scholarships based on very nuanced fit criteria and I wouldn’t take it personally.
They are both good options - at this point, given that price is similar, I would investigate the course and faculty options for prospective majors, ask yourself what kind of student vibe you seek, and if you prefer a more urban vs. a more rural setting.
Wash U:
African American 6%
Asian 16%
Hispanic 5%
International 8%
Native American 0%
White 56%
Out-of-State Students 93%
Dartmouth:
African American 7%
Asian 14%
Hispanic 8%
International 8%
Native American 2%
White 46%
Out-of-State Students 98%