Did I do the right thing?!?!

I'm sorry this is so long!!!

Ok so I'm VERY VERY VERY shy about my period and periods in general I know there's no reason to be I've had the "oh every woman goes through it" talk many times I'm just very self conscious. So anyway last week at school on Thursday I was at lunch and this boy who is the class clown and he absolutely HATES a teacher named Ms B. sat down at my table but I just kept talking with my friends and then he says he guys hey guys and we're like what Tim? And he says Guess what?! Yesterday in my parents room I found vampire blood left over from Halloween and tomorrow I'm going to put it on Ms. Bs chair so when she stands up I'm going to yell OMG MS B GOT HER PERIOD!!! And all of us said Tim that better not be true that's really mean etc and he said ok you'll see tomorrow. Tim lies A LOT to get attention so I really didn't think it was true. So then on Friday I have Ms B for first block and Tim is also in that class so I get into class and sadly me and my friend sit on either side of Tim ugh so when I walk into class Tim says Hey Emma and I'm like what Tim and he says remember what I said at lunch yesterday I said yyyyeeeaaaahhhh... and he said well I wasn't lying and I'm actually going to do it see then he pulls out his binder a tube of "vampire blood" and it looked really real! So I started to flip in my head because Ms B is one of my favorite teachers but I had had a traumatizing experience with my period that Ms B helped me with and I REALLY didn't want to talk to her about periods ever again and I also didn't want to be known as a snitch and Tim said to me he said I'm going to do it in 7th block we have her twice and we both have her for 7th block. And all through class my friend was like you need to tell Ms B she kept saying how bad will you feel if he does it you didn't say anything and she's crying?! And I felt horrible so right before the bell rang I went up to her to do it with my friend cheering me on I said Ms. B and she said yeah then I wimped out at the last second and said never mind and went to my next class well my next class teacher is a very very sweet young female teacher and I can't spell her name so I'm calling her Ms Br. So then I had an idea. So at the end of class I went up to Ms Br and I'm a very shy student and I don't normally go up to teachers desk or have a one on one conversation with a teacher so when I went up to her and started talking she was shocked lol and I said Ms Br and she said Yeah Emma what's up?! And I said well I need to talk to about something privately and I was VERY scared shy and tense at that moment and I think I looked traumatized when I said that because she said very concerned she said okay come with me and she lead me out into the hall and she said what's going on are you ok and I broke down I was so anxious and was very close to crying and I said it's nothing super serious and it's not about me but I have a very hard time talking about this. And she said Emma it's ok we are alone you are safe. And I said ok..... then I asked her if she knew who Tim was and she said no and I said well there's a boy in my first block named Tim and he has a plan to do something really mean to Ms B in 7th block and then I proceeded to tell her the story with my face going reder after every word and she said oh honey it's okay don't be ashamed of talking about that she gave me a hug and said I'm very proud of you for telling me that because that IS serious and I will be sure to inform Ms B and the office well then I started to flip and I said are you going to tell them I told you this?!?!?! And she said I was but if you don't want me to I won't and I shook my head no very fast and she said ok and gave me another hug and sent me off to class. Well Tim ended up finding out who told on him getting mad at me then getting ISS and a right up. But he is very angry at me and called me names and said I was a snitch who ruined everything! Was I being a snitch or was I doing the right thing???

*****Update

I'm not going to talk to the office because I could barely talk to my favorite teacher/teachers so I don't think I would be able to talk to a principal about that without wimping out or crying!😬 But at school today I did gather up enough courage to talk to Ms. Br I did it early this morning before 1st block started (once again in the empty teachers lounge) and I told her that Tim found out that I was the one who told on him and that he was giving me a really hard time and being really mean to me about it and then I asked her if anyone was around when she told Ms B and she said "no! Definitely not!" She said she told her when we went to explorations (that's classes like Band, gym, art, etc...) she said that Ms. B was in her room alone (there are no students on the 8th grade hall during 8th grade explorations and I'm in 8th grade) so Ms. Br walked into Ms Bs room and closed the door and then told Ms. B exactly what I said without ever mentioning my name. Then she said they both went to the office inside the head principals office with the door closed to tell the principal what was going on. Ms Br. Said that she was the one that explained to the principle what I said and instead of using my name she said that she used "a particular student" in replacement of my name. She said that then the principal took out a right up form and started filling it out and then the principal asked Ms Br if there was a particular reason why she wasn't saying who told her this (my name) and Ms. Br said that this student particularly asked me to keep there name private and that while talking to her this student was very nervous and is a usually shy and quiet student but this time was very anxious uncomfortable and crying because she was scared to talk about that subject. The principal then asked Ms. B if she knew or had any idea of what student Ms Br was talking about and Ms B said she had a guess then Ms B guessed it and got it right!!! And Ms Br. told her she was right. I'm not to surprised though because like I said before I had a MAJOR period incident earlier this year that Ms. B helped me through. Although Ms. Br and the principal were apparently very shocked and Ms. B told them that she had heard and seen how I react when it comes to the subject of periods and that I was the only student that she could think of that fit that description! Anyway the principal then asked them if I was a reliable source and I wasn't making this up. My teachers both firmly agreed I was and then the principal said that if they both agreed on that then she wouldn't call me down to the office to be questioned because of how shy and upset I was and that she would not tell Tim my name. So yeah he didn't find out through my teachers or principal I actually later found out it was my friend because she told her other friend who told her friend so on and so forth and Tim ended up finding out through them! Yeah she's not really my friend she's just a kid in school I like to talk to but not anymore I'm really mad at her!