On my previous video about age restrictions, I've seen a lot of comments from players trying to play Fortnite online, but are unable to due to being younger than the allowed age. This video shows that lifting the console parental control restrictions does not mean you can play age restricted games online.
There are two ways you can play Fortnite online:
(1) be the correct age or older. For Europe (PEGI), you need to be 12 or older. In North America, the game is rated "Teen", which you must be 13 or older. In Australia, the game is rated M (Mature), which means you must be 15 or older.
(2) own a "master" account on the PSN.
If you don't fall into either of the two categories above, you can't play Fortnite.