I took the leap.....it's go time

I told you so! It is a very busy process during the brewing stage and it's easy to overlook something. Even if you created a timeline/checklist it's difficult to remember to list everything on that. But don't worry about taking the OG before the yeast was pitched because the difference before/after is negligible. And if you meant that you didn't take the OG at all, then you can use the number that came with your recipe if there is one, assuming that you closely followed the recipe.