<human>: Hi /r/relationships

I get along really well with a co-worker. She goes back to university in 6 weeks - we'd cease to work together at that point. She's great and I would like to continue seeing her. We've worked together since January. 

At some point before she leaves I want to make it clear to her that I want to start seeing her outside of work.

Looking for feedback on when people think it would be appropriate to have that chat (notwithstanding any company policies) and any other advice you might think is relevant.

Or maybe I'm thinking about this the wrong way. Maybe I need to start seeing her outside of work as friends starting immediately, and then ask her out once we're no longer co-workers. Thoughts?

We have socialized outside of work once in a group setting. 

It's a workplace of 90 people. The job is very important to us both.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: Want to date co-worker in 6 weeks when we no longer work together; should I wait until the day before she leaves to make my intentions clear, do it now, or somewhere in between?