Congrats man, it was a scary experience the first time I did it, like I ran in there and ran out. The more you do it, the easier it gets. I don't know how, but it just does. I guess it's because the more you see that nothing happens, the more confident you get. The only awkward feeling is that it sounds distinctly different for a cismale peeing sitting down than it does for a pre-op transman, but I've learned how to make it nearly silent :3
Now, I walk around like a boss in the locker rooms, not giving a crap. No one pays attention to me, and if they do, it's a friendly word or two from a man to a man.