You need to plot your story when you write a series! That map really has to be finished before you can start writing! Dragons are overdone, and fantasy names should not be too common but also not too fantastic!
Do all rules keep you from writing? Do you become insecure because that advice one writer gives contradicts that from someone else?
Come listen to Kim ten Tusscher and discover that all is not so strict. Kim only made a world map seven years after her first book about Lilith has been published, and she wrote the successful series of seven books Tales of the Downfall being a chaotic pantser.
Share the writing advice you received with the group and learn to look at writing in a new way. Because one rule applies to all of us: everyone writes in their own way.