Firstly, it is important not to underestimate this task. Planning and executing the content for a new site is a significant commitment. Often once the build has begun, marketers return to their day job until two weeks before the site is live only to realise the enormity of the task ahead of them.
Your marketing agency should be highlighting the importance of your website content upfront. Not only because it’s a large task but also because content is probably the most important aspect to get right.