I agree with Miss E.
Not sure what type of job it is and how much training you need but some jobs, people are not competent in for 4 to 6 months. I don't think it is fair on an employer to put months into training someone if they are going to walk out the door a few weeks later.
I personally could not sit in an office knowing I was not up front with my employers and fellow workers.
Doesn't sound like you are overthinking it - you are just looking at it from all angles.