Would it be a bad idea to finish a RN program and go into a Pre-med instead of a BSN program?

I have gone to school for about a year and I have 50 credits, mostly to get into a RN program. But right after, instead of going for a BSN program, I want to go through the Pre-Med route and become a Pediatrician or General Physician. I just wanted to know if this sounds like a bad idea. I was thinking that I would finish the RN program in about 1 or 2 years, get a job, and go back to school and finish those extra courses and apply at a university and get a PhD. Tell me what you think and also how long it sounds like it would take. THANKS!