Freezing pumped breastmilk

Layla

Hi ladies, I had my little one almost 2 weeks ago and have been exclusively pumping around 30-40 oz a day. I’ve piled up a few bags (6 bags of 4-5 oz each) in my fridge which I know is only good for 4 days. When do should I start freezing them? And do you recommend I freeze the older ones first? I want to have some stash for when I go back to work in 9 weeks.