How to tell my brother i started my period?

First of all, let me say that I completely understand your discomfort when it comes to telling him. I know it's a very awkward thing--but it's only because it's new to you and you're young. I'm 23, I started when I was 12. Trust me, in a year or two it will be no biggie and you'll see that it's really not a big deal to anyone--including your brother. It's a bigger deal when you hide it. You actually have an advantage being he is a nurse. Nurses see all kinds of things because of the nature of their job. He will not think a thing of it if you tell him, promise. He knows you have to start sometime, and he may end up concerned if in a few years you're to an age it's a problem you haven't started and he thinks you still haven't. Just tell him, sweetie. You'll feel better not having to hide your bad days, tampons/pads in the trash can, and being able to let him know when you need something. It will be fine. And I'm also terribly sorry for the loss of your parents. You're in my prayers. Take care, hun.