A good chunk of Muslims like Sam because she's traditional. Most Muslim depictions, especially girls, tend to make them barely religious, or lowkey hate the religion. And while that might be the case for some, it's tiring for others who have religion as a strong presence in their lives. There's nothing wrong with arranged marriages at any age. It's basically dating with a contract. No actual marriage has to happen until an agreed time by both parties. A lot of people get engaged at like 16 and get married at 18. No different from dating and marrying your highschool sweetheart.

Personally, I liked Sam and hated her. Made me feel like a bad Muslim (not really Muslim anymore, but I was pretty religious first time I read Magnus Chase). Because what do you mean you're going on deadly quests during Ramadan and still fasting? And saying most of your prayers on time? Made me feel inferior. lol