Iv been given a creative director as my first job and am developing our visual identity from scratch.. We are an outdoor media owner.. If created a simple cartoony style for all our illustration.. Can I update this and make it evolve as I go along?
Most all identities evolve over time. There should be some shared DNA, but trends and styles come and go and brand identities tend to follow along.
Absolutely! Whether or not it should is a different topic, but just look at the battle between 'flat' design and the skeuomorphic designs of the early 00s.
We're actually living in a fascinating time for this topic, as the 'flat' design trend is becoming so overwhelming that we're seeing brands that haven't updated their style in ages pressured into removing the third dimension from their identity. Now we have millions of lazy designers co-opting the "material design" guidelines released by google.
But in answer to your question, definitely. Your brand identity should stay relevant to the time you're living in, and your current identity should be a choice made by you, for the betterment of your brand. Keep the core elements firm, and adjust to what your brand currently needs to stay relevant.
Or don't! But if you choose to not update, make sure that that's a choice you're making on purpose.