<human>: Give me a shortened version of the text

I got offered an entry-level job last week at an insurance firm in a city about an hours commute away from me, through an agency. Before I'd heard back from this job, I got an interview for another job and agreed to attend on Wednesday. I then heard back from the first job who offered me a position and I accepted it. 

I'd much prefer to have the 2nd job (the one I have an interview for on Wednesday) because the hours are better and it pays more, with much less of a commute. There are 3 people including myself interviewing for the job on Wednesday so it's by no means guaranteed, but I'm not sure what to do. I want to let the people at the first job know that I can no longer accept the position, but I'm due to start a week tomorrow and want to give them as much notice as possible. I won't find out if I have the 2nd job until the end of the week.

Where do I stand with telling the 1st employer I no longer wish to accept the job? I feel terrible, the guy that interviewed me was lovely and the lady at the agency has been really helpful but ultimately the 2nd job is much better for me.
<bot>: Accepted a job but have an interview for 2nd job which i'd prefer. Not sure what to do.