Can a site with protocols for tournaments among schoolchildren have problems with the law on the protection of personal data?

Question

Personal Information

Hello, friends.
On a voluntary basis, I am writing a site for regional tournaments of young physicists , school and / or student. The purpose of the site is to store tournament protocols for several years in one database, which also include the full names of the participants and their schools/universities. These data are sent by the team leaders themselves as part of the application for the tournament, and then entered by the organizers into the database.
The development is already nearing completion, but suddenly legal questions arose:
- Is it possible to post this data on the Internet at all?
- As far as I know, just a full name is not considered personal data, but what about the full name + school or full name + city?
Do I need to get written permission from each participant?
What if the participant is a minor?
— Who will be considered a personal data operator if the organizing committee of the tournament is not officially registered in any way?