Summer program at UCLA or BROWN?

I am a junior in high school and I want to go into premed. I applied to COSMOS for Biomedical Science in January and am still waiting for their response. It accepts approximately 1 in 3 people (or so they claim). I also saw that the Ivy Leagues offer summer courses for medical-related subjects as well. I want to go to Brown over the UCs. Would it be better to go to the COSMOS or the Brown program during the summer?