Curious About Islam – Some Honest Questions

Assalamu alaikum, everyone. I’m a girl from a non-Muslim background (the only one in my family who isn’t Muslim) and I’ve got some things on my mind about Islam. Hope it’s okay to ask here. First, has the Quran ever been changed or rewritten over time? If not, why? My parents always say it’s never been altered because it’s a holy book and Allah Himself protects it from being edited. But since I don’t really believe, that explanation feels a bit impossible to me-unless there’s a different reason why it stayed the same. Or maybe it was actually changed at some point?? Second, I’m wondering-should a Muslim man be more peaceful or ready to fight? I once told my mom that if I ever have a son, I’d name him something that means “calm, peaceful man” in my native language. She didn’t like it at all and said a real Muslim man shouldn’t just be peaceful, he should be a warrior. I didn’t argue, but it felt strange, because I thought Islam is a religion of peace? Another thing-why are some things only done with the right hand or the left? Like, why is eating with the left hand not allowed? I honestly don’t get the reason behind it. Fourth question: why do we have to love Prophet Muhammad (I think I’m supposed to say peace and blessings upon him, but I don’t fully understand that either) more than our own parents? My mom literally cried once while talking about him and said she loves him more than anyone in the world, even her parents. I just can’t wrap my head around it-why cry that much for someone who lived so long ago? Is this something common in Islam? Lastly, I’ve heard about people who were born and raised in Muslim families but later left the religion. Why does that happen? Were they ever really Muslim to begin with? I’m asking all this because my parents, especially my stepfather, keep pushing me to become Muslim and start praying. This has been going on for about four years. I think they’re uncomfortable with me not believing. My father even says if I don’t accept Islam soon, I’ll be in big trouble. To be honest, I don’t really want to join, I’m only going along because they ask me to.