Applying FOMO on life isn't worth it IMO. If you could be happy with just one thing (and it's safe and cheap), then you're one step closer to winning at life. If you fell for the FOMO, then you will be unhappy no matter what. Coming into each decade/milestone of getting old, you will always worry yourself with what you don't have or haven't done.
The only thing convenient about her characterization is that she's from an all-girl's school. Speaking from experience, she's a type who is not particularly that unusual as far as hobbies go. But maybe it's different for Japanese people.
Edit: actually, after having read the later chapters, I'd say it's the guy MC who is more of a catch. It could be said that he's also unrealistically convenient for the heroine.