Not able to decide whether she loves me or not

I come in touch with a girl in my office. At first, I avoid her but she comes more & more close to me.

She starts confiding in me everything about herself, i don't know why she is telling me everything. She told me something which I never think a girl can share with unknown guy...

She confirms "I tell you things which I don't share with other friends"

I started having feelings for her and don't know since what time. I tried myself not to fall for her but still can't get her out of my mind..

Now she still talks to me and shares with me lot of things but now when she talks to other guys I start feeling jealous.

I have sometimes asked her "why r u sharing this with me?" and have got reply like "because you hear to what I say"

For last 4 weeks, I have not been able to decide whether to tell her my feelings or not? But I have been hanging around her wherever she goes, listening to her, helping her in work.

I think that she knows that I love her coz I am only one sticking with her always. Recently I have acted more stupid by changing my place when she changed her place.

I am still confused whether to tell her my feelings for her?

She is 5 years older than me & I am 26.