What is the age of the youngest known Bitcoin developer? What is the youngest age of someone known to have submitted a Pull Request to Bitcoin Core?
https://github.com/whitj00

Whit Jackson, 15 is the youngest I can find. Github does not list the ages of PR authors:)

http://www.coindesk.com/15-year-old-developer-ethereum-whit-jackson/

edit: I am not sure of his exact birthday. He may have been 14 when submitting this PR for bitcoin.org:

https://github.com/whitj00/bitcoin.org/commit/b3ef809c7c63c9ededa4f4ad40ef5ff314434fe8