I think you're getting great advice here. Radiation is tough but dying in your twenties is a hell of a lot worse. I know it's a scary prospect but, as others said above, it's not the end of the world. I finished radiation six months ago and I am feeling really good at this point. Please talk to your doctors in depth to get a clear idea of why they are recommending radiation and maybe read through some of the stories on this forum to better understand what it will be like. If you still aren't sure, get a second opinion so you can be confident in whatever you decide.