Should I Spend £900 or £1,600 on My First Road Bike?

I’ve been cycling pretty regularly for about a year and I want to buy my first proper road bike. I’ve found one for around £900 that honestly does everything I need, but there’s another one for £1,600 that’s lighter, has better components and would probably last me longer. I can afford both, I’m just not sure if I’m serious enough about cycling to justify spending that much.