If she was an adult in Korea I could understand if she cried after she reincarnated because it's a stressful situation to find out that you can never see anything you knew ever again. But crying all the time cause some tiny brats bully you when they're not very smart is... also not very smart writing. I usually let a lot slide in these stories on account of them being fantasy and the trope that being in a child's body makes one feel and act more like a child. But really? A whole adult weeping cause some kids say mean things to you?
So far the isekai thing seems to only be present so that she had a reason to be good at working in her (second?) life, rather than... you know... having a character who's a natural genius; like the male lead, or the male lead in some other story, or the male lead in literally every other story.