If I mention “dialects” to you in respect to Irish Gaelic, it might make you fret!
First off, as we say in one of our members’ lessons dedicated to Irish Gaelic dialects, you most surely should not fret about it as a beginner.
In any case, you do know dialects. Look at North America, and the number of variations across that great region, even if you understand all variations.
Rick Aschmann has a hobby. That hobby is collecting information on North American English dialects. Look at the snippet of his map to the right of dialectal variations.
He has amassed a huge resource, and it’s worth checking out his detailed map and region descriptions.