Confused at actions...

Just a bit confused at some actions, of a languages teacher I've attended for some time now (about 18 months).

We've developed a casual friendship, but I want to take it to the next level and become closer. I admit I am attracted to her physically and emotionally/intellectually, but then I'm not sure she thinks the same way.

The things is we talk often via e-mail and stuff, and about some personal stuff like goals, desires, she says she wants kids and a girl not a boy. and some personal stuff I won't say here about her past.

I told her a little while ago that I am thinking of going away to my home country as it better suits my career aims. She said she'd be depressed, because she initially misunderstood this and thought for sure I was leaving. I've wanted to learn Mandarin and Hindi (what she teaches) for a while, and I'm grateful because my firm has some jobs in China and India, and said in gratitude that I wanted to take her to lunch just before I leave (if I do, I'm still pondering this...)

She invited me to a art gallery opening the other day. And a type of art I like (modern) but I couldn't go. I met her again the other day and said I was sorry not to attend but she said it was OK, because it was a general thing and not a personal thing.

As said, I am attracted to her, and knowing women (well humans since men can know also if a woman likes us) I think she can sense this. However, whilst she is pretty and has a good personality, I don't think I'm her type. Even still, I want to be friends, but am not sure how to make the leap as it were. I get that she likes/respects me, and yes, we're just casual friends but then as said, I'm not sure how to make the leap. I think it's because I've never had much female friends before, and now as an adult I find most of my friends/acquaintances are women. In honesty, this is compensating for when I was a teen.

I'm essentially confused if she wants to be friends, or is just being casually friendly, because I like her a lot. This is tll;dr granted, but then I had a lot to jot down.