So, today I went to a landscape painting event in a park. There were a lot of nice-looking girls, and I talked to a bunch of them. I managed to have a nice, casual conversation with one of them about painting. I was confident in my approach, but I wasn’t flirty at all, because I didn’t think it was the right occasion for that — but she was pretty receptive to me.
By the end of the event, she asked me, “Where can I see your work?” (I’m a professional artist myself), so I gave her my Instagram.
She followed me and liked one of my pictures.

So, my question is: when is the right moment to text her? Should I do it right now? (This was about three hours ago.) Or should I wait a bit longer? What’s the best approach?
Should I be direct and tell her she caught my attention and ask her out for coffee in the first message? Or would it be better to take it slow and wait to comment on one of her stories and start a casual conversation?
I’d appreciate your help so I can come up with a good strategy.