I met a girl and went out with her once about a month ago. We went to the woods and spent the day walking around. I feel like it went really well and I made a good impression as I am always in a really good mood when I am out in nature. We talked a lot. I tried a few different techniques but mostly I was building comfort and showing interest in her as a person. However she resisted my physical advances and told me about how she ended a 5-year relationship a few months ago. She did ask me about my sign though, said I had a nice smile and didn't seem to mind or be uncomfortable when I had my arm around her for a while.
Since then I have tried to get together with her a couple of times, but unsuccessfully. The first time I invited her to go on this event where we form teams and go around town taking photos (we are both into photography) but I had to cancel it as I had forgotten about something else I had that day which was really important! A week or two later I told her I was going to a painting workshop and invited her to come along. Her answer:
"Didn't know there is such an event But right now I don't feel like I will join you, my mind is in too big mess, but will see how I feel on Sunday." (Sunday was the day of the workshop.). I told her I understand and to let me know if she is up for it. This was about three weeks ago and now I'm wondering how to proceed.
I feel like if I invite her out again I may be chasing too much, but if I don't I will not hear from her again. So I'm thinking about sending her a Facebook message, that way it will be more casual. Maybe I will just flirt with her a bit, maybe I will also invite her to a festival this weekend, or maybe I should try to find out where we stand? I am worried that she is uninterested because she is 21 and I am 32 (if you read my previous thread, this is another 21-year old

). I'd really like to know if this is true so I can move on from her. What do you think would be the best way to message her on Facebook?