Hey @MoonShadows 

Don't worry, it is not "just you".

Over the past year plus that I've been playing I have had 4 different violin teachers (due to moves and one retired).  At every one... without exception... I still get nervous.  And every one told me all their students do.

Here are a few tips. 

Practice! This is perhaps the most important tip I can give you.   But make sure you practice what your teacher tells you to work on.  This is part of being prepared.  YOUR lesson will go much better, be more productive, and you will have less anxiety if you have been practicing your material.  Also, your teacher will notice and will compliment you on your progress. This goes a LONG way to helping you feel at ease.

Remember that you are paying to have someone teach you, not necessarily critique you.  If you played perfect violin, clearly you would not need lessons.  Your teacher knows this.  A good teacher will not make you feel you are failing or be judgemental of your abilities.  So go to your lessons with the idea that your teacher is there to help you become a great violin player.

Also, you are not performing so do not feel this is a test or evaluation of what you worked on.  Again, your teacher is aware you have areas you need to work on and her job is to help you with those areas.  The idea is NOT... "here is your assignment, go work on it for a week and we'll see how you do when you come back."  The role of your teacher is to provide guidance and give you methods to improve your playing.  She is not evaluating you on whether you completed your "assignment" or not.  This is a mentality we have learned from school.  When we turn in school homework it is then graded and we are given a score.  This is not how private music lessons work.

Some of my nervousness comes from questions I automatically ask myself... have I practiced enough?  Will my teacher be pleased/accepting of me?  If I keep making the same mistake will my teacher think I cannot overcome it?  Am I a good student?  All these questions are irrelevant because it is not my teacher that I need to impress. I am learning a difficult instrument which takes time and dedication.  And none of those questions will help me play better, nor will they help my teacher help me.  

Mistakes are good!  Do not be afraid of them.  The place to make mistakes is during practice and your lessons.  Your teacher needs to know what areas you need to work on.  She needs you to play and try and make mistakes.  Then she can be much more help to you.  When you play a piece perfectly, she has no advise to give you.  But the mistakes will tell her exactly how to help you.

Try not to worry too much.  You are about to see your playing skill skyrocket compared to the three months you have been self-teaching!  Not that there is anything wrong with being self-taught.  It just moves faster when you have a teacher.

Hope this helps!