I would strongly recommend that you load a few first (50 still sounds like a high number). Load maybe 10 - 20 rounds and test fire them before continuing any further. This is a great way to "QC" your work. It's better to find out sooner than later if you made any mistakes. I had a friend load 500 9mm rounds once. We got to the range, fired the first shot out of his CX-4 Storm and realized that all 500 rounds were "squib loads". Apparently he used some automatic powder scale. I was "eyeballing" his work while he was loading, and thought that the powder charge looked a little light. He assured me that his "high tech" machine was accurate to the single grain. Apparently his "high tech" machine was on the money, the operator on the other hand had made a grave error in setting the weight of the powder charge. Luckily nobody was hurt, and I had brought along a bunch of factory ammo. ;) This is the same guy that once "loaded" two muzzle loading rifles while we were doing a public shoot only to find that he didn't put any powder down the barrel.
Key thing to remember when reloading is to check and double check what you're doing. If possible triple check and maybe have an experienced helper around. Keep your distractions to a minimum. The wrong powder charge, primer, etc can have serious consequences.