<human>: Hey r/relationships,
This is probably routine basic stuff for you guys out there who have dated more. There's nothing wrong with me but I haven't dated much. I don't know how to flirt.

There's this coworker who I think is really cute, we have a lot in common (sense of humor, laid back and slightly cynical view of the world). For a while I had a feeling she wanted me to ask her out. In fact, around two months ago she said we should go for drinks with our other coworker. It hasn't happened initially because of our schedules but more recently she's seemed a jaded / indifferent (she says she can't afford to go out, which I believe). As I said, I'm not good at flirting but we always kid of joke around at work. I guess it's my idea of flirting which is very difficult to interpret for women.

I wasn't confident enough to ask her out sooner. I really want to do this. I'm leaving my job (and city) in four months and this is really the last chance for us to date.

Obviously, the coworker thing is tricky. Maybe this isn't a smart plan, but I'm not that concerned about dating a coworker (we don't work directly together). 

I think I should just ask her out. Why am I struggling?

Can you succinctly summarize the text in 1-3 sentences?
<bot>: overthinking the problem, old enough to know better but inexperienced; need to ask out coworker, requesitng that someone show me how.