Pictures from my install: Install Videos and Pictures 🩸 - #269 by StarGate01 . No anesthesia, pain was ok. During the process not as bad as a beestring, afterwards a bit of annoying pain but it calmed down after a few days.
Flex install guide: https://forum.dangerousthings.com/uploads/short-url/3ZvkX7KKfFxuC7fWTP6lVKER3Bq.pdf , Professional Flex Install Guide?
However, consider that your arm will still grow as you get older and things will shift around. Also, you will have a hard time finding an installer willing to operate on minors, especially if your parents don’t consent.