do 3 years catagorical IM, then follow that w/ a endocrine fellowship... good luck dude
endocrine is a nice field for the "family-type," you can have a "life," but the pay is not that much different from an internist... good luck
People going into certain specialized residencies (dermatology, anesthesiology, radiology, some ER) have to do a preliminary or transitional year first.