I feel like it's pretty realistic actually. This is a normal mechanic of human relationship: you get attached to a group which welcomes your presence.
If a group of people (not necesarily all of them, just a significant part) shows that a. You have something special and b. They appreciate your presence due to that special-ness, then you are very likely to form rapport with them, get attached to them and willing to protect and help them in return.
Very few people are immune to this effect, introverts and generally 'not-good-with-crowd' people even less so. As a matter of fact, they are especially targeted by cults with the same mechanics, luring them in by boosting their sense of self-worth and subverting them for the cult's gain.
I'm not saying it's what happening here, but it's understandable why the MC values the group so much. The kids pretty much idolized her and in turn she feels a sense of obligation to meet their expectation. Imagine if you are not too popular at school, then suddenly the whole school gathered to cheer for you in a competition. That will certainly give you a big dose of motivation.