That depends on what you want to do ultimately.
If you want to be a transport RN then most programs want to a couple of years of ICU nursing experience, and having you medic helps immensely. Most ground and air transport programs run mostly IFT (75-80%) so ED nursing is of much less value to them, especially when they have an experienced paramedic. (In comparison our prehospital group does no IFT and we attempt to stabilize patients in the field without taking them to the hospital so we want ED nurses and rural 911 experienced paramedics, we are very much an exception though.)
If you want to be a flight/cct medic they want to see several years of heavy 911 experience, and generally require additional certifications in critical care paramedicine.
If your ultimate goal is to be a ED or ICU nurse I wouldn't necessarily focus on getting your medic before nursing school. While having your medic would help you to get a critical care job over getting stuck on med/surg good EMT experience will be almost the same from a hiring standpoint.
