Hi. Hm, that does seem odd if you've had it since birth and it happens in reaction to stress and anxiety. Anxiety shaking is not uncommon. https://www.healthline.com/health/anxiety-shaking This article describes something called 'flight or fight'. This is a basic human reaction. It's something we are born with. When your body perceives something harmful (fear of something, anxiety, nervousness besides just real danger of things that could hurt us physically), your brain reacts. Fight or flight. Your muscles contract, tighten. This in you may result in these tremors. Typically teaching someone how to relax in those moments, (slowing down the situation, deep breathing, etc.) is what doctors and psychologists recommends. Identifying the triggers and dealing with that too. What else went into a parkinson's diagnosis? Are they saying that anxiety makes the tremors you'd have any way more pronounced and worse? Anxiety will make tremors worse. But I would be shocked if you had parkinsons 'from birth'. here's more info on anxiety tremors and what you can do about them. https://www.calmclinic.com/anxiety/symptoms/tremors
Here's a guide on parkinsons. https://www.webmd.com/parkinsons-disease/guide/diagnosing-parkinsons#1
I would also look into essential tremor. Much more likely than parkinsons.
I'm 47 and have always had shakey hands. It gets worse when I have to write in front of someone or when nervous or stressed. My kids are the same. It has to do with anxiety. Does this happen when your alone or in public?