How to handle leaving a family business?

So hear me out: I once worked for a small grocery store that my aunt and uncle owned. They had two registers, produce and meat section. My cousin (their son) also works there. At first, he would work the register and check people out while I stocked shelves and produce and eventually learned to cut meat while my aunt and uncle helped where they could (receiving things in the back or office work). Eventually got trained to work the other register so I pretty much knew how to do everything. After that, my cousin started showing up less and less. His parents had to start doing more grunt work since it would only be us three working the whole store. After a few months, I realize he was being lazy because no matter what, his parents would never fire him. I got upset over this and secretly started making plans to find a new job. 

One day after the store closed, I called my aunt, uncle and cousin to the office to tell them that I intended to move on to a new job and that I was officially giving them my two weeks notice and will work to make it a smooth transition while helping them find new help. My aunt and uncle seemed mad but my cousin said "WHY WAIT? IF YOU WANT OUT, THEN LEAVE TOMORROW. GET THE F*CK OUT!" which shocked me since his laziness was a big reason to me wanting to move on. Anyways, I left the next day and have been in my new job for 6 months now.

Even though it was a family business, was my reason for leaving ok? Did I handle things well? I feel some guilt. Thanks.