You must have British nationality to be eligible for a British passport.
An adult passport is valid for 10 years.
Apply for a first adult passport if you’re aged 16 or over (or will be within 3 weeks) and never had a child passport.
You can use your child passport until it expires, even if you’re over 18.
Follow the process for getting a first adult passport if the last passport you had was an old black or blue passport.
There will be no change to the rights and status of EU nationals living in the UK, nor UK nationals living in the EU, while the UK remains in the EU.