Happy to weigh in as a younger diagnoses person
I was diagnosed at 39 with ET
I am now 68 and just fine living with it. Idk where this 30 year survival rate idea originated from but my research say normal life span as long as it is monitored.

I was started on HU immediately and looking back I feel that was too aggressive for someone my age with no symptoms or health issues.
Long term use of HU can cause problems and I got very bad case of Basel cell carcinoma.
I wish I had gone for another opinion and perhaps considered more seriously the baby aspirin option. The doctors scared me with the possibility of stroke.

I switched to Anagrelide 5 years ago and doing fine with it.

ET was formerly known as a blood disorder NOT cancer. That designation changed in the last few years for whatever reason. (Some say to acquire more research funding)

This is my story and I hope it helps.
How you proceed is your choice and I’m glad you are here asking questions.
So me- I would have stayed off any drugs for this until I was older if I knew then what I know now.

You can live a long healthy life as long as you keep up with your hem and stay vigilant about your health.
Best of luck to you!