My first razor was a Fatboy. It's not going to really change up that much when you shave. Some people seem to talk like adjustables use a random number generator every time you pick it up or something. Pick a number and give it a couple shaves, if it's too mild or too agressive even once you've got the angle figured out then adjust it accordingly. An adjustable is not the be all end all of razors, but it is great for seeing how you react to more or less aggression and it's also a convenient measuring stick. If you've used a certain adjustable and someone compares another razor to it on such & such a setting, right off the bat you have a good idea of it's aggression. That's why in my shavewiki which I am using as a personal log to keep track of what I've used I compare each razor I try to my Fatboy, both in how the shave feels and how close the shave is. That way anyone reading it can see what I thought of each razor and easily see how different I felt each razor was. So don't be afraid to grab an adjustable, load it up, shave with it and learn from it.
Kids are wonderful, but I like mine barbecued - Bob Hope