I don't see much wrong with your plant other than possible the red stems on the fan leaves, which is very minor. I see the brown spots you're speaking of, but it doesn't concern me. It can happen to a leaf or two during dry spells in the soil. Speaking of nitrogen, if you ever have nitrogen toxicity , the edges of your leaves will curl up extremely. But, before that ever happens, usually you will notice burnt fan leaf tips. Good luck!