I applied to HPME in high school but I got rejected before they even gave out the application. I still got into NU anyways and just got into Feinberg through the NUPSP program (early admission but for NU undergrads and you apply at the beggining of Junior year). Just goes to show, getting in through HPME does mean you wont get into Feinberg.
Actually, most people aren't ready to make that decision on their own until after they have experience in undergrad. After all, HPME pretty much expects you to have clinical experience and research and volunteering all within your high school resume. As someone who does not have parents (or even extended family members/family friends) in the medical field, this was not a possibility for me in high school. However, through my connections on campus, I was able to find the opportunities I needed to explore the medical field. Conclusion, apply if you can, but dont take it to seriously if you dont get in.