Do I need technical skills?
To publish, no. To install, knowing how to upload files and create a database is enough.
Can I use my own theme?
Yes. A theme is a folder of templates and styles, documented in the documentation.
Do updates break the site?
Database migrations are automatic and reversible, and every release is tested before shipping.
Do I own my data?
Entirely. A full export is available at any time, in no proprietary format.