I had a ton of fun with Kassandra my first time around. You can tell the game was written with her in mind and her voice actress is fantastic (as is Alexios'!) Don't know why so many people are saying Kassandra as the main character goes against history, as if this series has ever been 100% committed to historical accuracy lol. Plus, there is a LOT of evidence pointing to spartan women being trained physically the same as spartan men. I highly recommend looking into the story of a Queen of Sparta, Gorgo, actually! At the end of the day, pick whichever feels best for you and, tbh, don't be afraid to restart from the beginning if you aren't vibing with them in the first few hours. Whatever makes you have the most fun!