Fantastic - congrats! That takes guts.
Coming out is scary at first, but it gets easier the more you do it. It's good to hear you have some IRL support at school. Do feel free to talk to her, especially if/when you feel like coming out at school. She'll be able to help you manage it, and she can make sure that the staff will have your back if anyone gives you any trouble.
I presume it made you feel relieved then?