How do I interpret her behavior?

Alright, so - I'm 22, she's 27. Now before you say she's quite old for me or something similar, please read on.

Her behavior is like she's of my age; we guys are classmates, and she often calls me up to meet together and help her out with the studies (unfortunately, she has a joint family, which means we never meet at her house). I really like her and even touch her casually while we are talking and discussing something funny. She does the same.

We both say stuff like 'love you darling, sweetheart, honey, etc.', but I feel that's still kinda casual.

Off late, I find myself slowly becoming used to her. I enjoy her presence and do quite a lot possible to see her happy. Every time I try to make a serious remark about loving her (I think I somewhat do, because I find myself going above and beyond to do what makes her happy, and it's just that 1 person. I do not do extra for anyone else), she kinda ignores that - as in she doesn't respond back with something similar.

She only asked me about going out together once and then we both got busy with our work and study lives; 2 things I noticed about her are: her mood can change easily, and she is mostly restless (similar to being overly active), as in I don't see her calm usually. Also, when she arrives at the school for the classes, she only speaks to me the most, and to nobody else (as in, no other guy).

So, how do I find out whether I really have any chances with her? Or is it a dead-end? Is she using me?