National Living Wage In The UK

Not sure if there is already a post on this so feel free to delete if there is :)

Most countries recognise people as adults at age 18 or 21 and here in the UK a 21 year old is an adult in terms of all laws (please correct me if I'm wrong).

In the uk we have minimum wage and national living wage, the living wage is what is deemed to be the minimum hourly rate a person can reasonably live off however you don't get paid living wage until you're 25.

As a 22 year old living with my partner I would only be paid minimum wage which is a fair bit lower than living wage. To me this is like saying 'you're an adult but you don't deserve to be able to live'

If I were to commit a crime I'd be held responsible as an adult but 'living wage' isn't a requirement until I've legally been an adult for four years?

My question for everyone is this:

Is it wrong for living wage to only be compulsory for those ages 25 and over?

(I'm really interested in what people think on the matter, please forgive my appalling spelling and grammar my phone hates this app and has a tendency to change words at random, I'll post the rates for minimum wage and living wage in a comment below)