Peabody & JHU Double Degree Question

Hi!! So I recently just received an offer from Peabody. However, I am thinking of applying for the dual degree program with JHU in my sophomore year for college.
The reason I did not apply that for the first place is that I thought my high school grades and the SATs were not good enough. They are decent but certainly not at the standard for JHU. I thought it would be better if I apply to Peabody first and then apply for the dual degree when I am in college.
But I am still not sure whether that is doable. After calling the admissions at Peabody and asking about that they told me it's like transferring to another university. I just really want to know how hard it is to apply in the university and what is needed to apply for that degree. Are high school GPA still very important or they care more about the grades in college?
Thank you so much everybody and I would be so happy if somebody within the dual degree program can answer this for me.

I apologize for the late reply. My daugter knows a few Homewood students who are dual degrees with Peabody. And it is rigorous and not for the faint of heart. Time management and organization is key because of the rigor of the music program (congratulations on Peabody!) as well as course selection of Homewood courses. The campuses are about twenty minutes apart via shuttle which also needs to be factored into the scheduling.

The dual degree takes five years to complete. I’m sure you have read the information on the Hopkins website but I’m linking again for you here.

http://e-catalog.jhu.edu/departments-program-requirements-and-courses/multi-school-programs/peabody-double-degree/