(33M) She's amazing, but I can't read her because I'm inexperienced at dating and socially inept

She's 25F. Smart, funny, hard-working, quirky, beautiful. (So beautiful!)

I'm 33M. Overweight, weird, nerdy, Aspergery. I'm told I'm witty and charming.

We worked together 2 years ago and I developed a crush but didn't act on it because it was work and that seemed wrong. (It was a job in politics. A campaign. Only later did I learn that everyone but me was either going out with or sleeping with everyone else.)

I figured I'd ask her out after our work together ended, but she started dating another guy. Like a real man. A veteran of war.

I kept in touch with her over the months. Her online correspondence always seemed flirtatious, but I knew she was unavailable, so it only confused me.

A few weeks ago she asked me to dinner. I agreed. Then I found out from someone else that she and Mr. War Hero broke up recently. Was this dinner more than platonic?

The dinner was last night after work. Local restaurant & bar. Not a romantic place. We talked for 2 hours and had fun. However, she didn't seem as flirtatious as she did in all the online chats and emails we would have.

I am very slow socially. I haven't had many dates and my only real romantic relationship ended 11 years ago. I can't read women. I over-analyze every word and hug and piece of data. (Monday at 5:30pm may be the least romantic time of the week.)

How do I do this? I don't want to make her feel awkward. I don't want to force her into something so quickly after a break-up.

I'm also deathly afraid that I've misinterpreted our entire friendship. (You thought I was interested in you romantically?!) Does she see me as a single guy or as a big brother?

Thank you.

tl;dr Girl I had a crush on 2 years ago asked me to dinner when I thought she wasn't single. I learned after accepting that she is single. I'm a social moron and pick up on cues.