How much will the work or purpose of a nurse change over time?

I'm 15 researching for a job in the nursing field. I want a career that doesn't change to much. I want a career that I can count on to stay the same for years to come but how much will it change? I know we learn new stuff in medicine everyday but How much will the principles or purpose of the work change. I don't mind a little bit of change I just don't want the entire game to change on me.My whole family are nurses,dad, mom, sister and her old boyfriend she had a baby by. I want to be one in the military but I don't like change.