"ELIGIBILITY. The Contest is a skill-based contest open to individuals who are at least age eighteen (18) or older or are the legal age of majority in the jurisdiction in which they reside and capable of forming a binding contract with Sponsor as of the date of entry, that are DEV Members (defined below) and have an active email account and Internet access throughout the Entry Period. "
It looks like that according to the official rules you need to be +18 in order to participate:
dev.to/page/official-hackathon-rules
Oh sorry, I didn't see that.
Thanks for telling me.