Hello, I am currently studying astrophysics in my undergrad. I am concerned with the fact that I do not know what field I want to explore during grad school yet. I am in my junior year and will probably finish my undergrad in five years due to double majoring in math as well. I realize I have huge interest in nuclear astrophysics and cosmology. While I currently am conducting research in nuclear astrophysics, I feel I may discover that my interests are in cosmology more. Would switching research interests in my undergrad be detrimental to grad school? I am concerned as some of my fellow classmates are dead set on what they wanted to do since entering university. I did not have this mindset as I wanted to explore my interests and now I feel I have narrowed my interests down to these two areas.