Great job on starting the journey. After you gain more experiences you'll lean to move the thicker and wider steel where you want it.
Regarding thickness, you may have read or seen Karl's saying that goes something like,
Forge it thick and grind it thin for the blade lies within. That's the essence of his quote, at least. He has also described it as scraping the burnt carbon from a piece of toast to get to good toasted bread underneath.
Also keep in mind that you will be stepping through various grits in grinding and you have to allow enough material to be at final thickness on your finishing grits.
I have had a tendency to make blades that are overall too thin or I leave the edge too thick. Master Smith Tommy Gann has helped me better understand that I need to keep my spines thicker and get my edges thinner.
Good luck!