Monzo shared these stats on the Facebook page today, which show that there’s still some room for growth in the number of older users 
emphasis mine
If there’s one thing we’ve learnt as the Monzo community has grown, it’s that openness to change isn’t always related to age. Some may assume that a mobile led banking app is a product aimed squarely at people who have grown up with Uber and Instagram, but ultimately we’d like to think we’re working on solutions to problems which every generation has in common. Frustration with traditional banking is nothing new, as we’re sure our oldest users (who are in their 80’s) can confirm! The possibility of being able to offer some sort of financial service and education to young people under the age of 18 in the future, is something which really excites us too
We look forward to welcoming more users of all ages and and creating an awesome and accessible product with their help
