NCI or Johns Hopkins?

I am currently a High School Student and I have recently been offered two Internships. One at the National Cancer Institute in Bethesda and one at Johns Hopkins Bloomberg School of Health in Baltimore. Both are paid and housing is not an issue. Which Should I Accept?

Also:
At National Cancer Institute, I will be working aside a mentor on her project; At JHU, I will be working on a project (with the help of the professor) that I have proposed. However, my parents want me to accept the offer from the National Cancer Institute because they say it carries much more prestige.