Chances for brown?

GPA: 5.07 weighted/3.96 unweighted
Class rank: 3/270
ACT: 31
SAT: 1970 composite
Classes: 9 AP’s total/all honors
Mostly 4’s on AP exams
Leadership:
President of Spanish club
Captain of mock trial team (3 years, best attorney and witness awards)
Secretary of national honor society
Secretary of math honor society
Senior representative for key club (junior of the year award)
Extracurriculars:
Teen republicans
Tri-Chi
National Honor society
Math honor society
Spanish honor society
Asia club
International thespian society
Mathletes
Other:
60 hours of volunteering at local history museum
60+ hours completed for an int behind with local republican headquarters
Co-owner/founder of an etsy shop with my sister
Attended the Governor’s School of North Carolina in summer of 2015
Attended Journalism camp at UNC Chapel Hill
Worked with vacation bible school in the summer

PS: I already interviewed with Brown and my interviewer said I was a shoe in, but I feel my scores aren’t good enough.

You are right to have that feeling, as your scores are very low for Brown, especially for RD. In my opinion, you would have to be hooked to get in with your profile, as the test scores are really gonna hurt you, but I understand why your interviewer would say that about you. The rest of your application looks very impressive, and your interviewer doesn’t know about those test scores. That may actually come in handy for you, as your interviewer may be able to write a killer report about you that will show something different about you. But, as with the tens of thousands of other Brown applicants who applied RD, you will almost certainly be rejected unless you are URM/major donor/double legacy.