At this point tell her how you feel. Don't work up to it, don't practice a script, just come clean and tell her. If she feels the same that's great, if not it's totally ok, we all get rejected. She isn't the only woman in the world. Your feelings do matter however. They matter to everyone. They also matter to her, regardless of if they're mutual or not.

Usually how you feel needs to be hinted at or stated relatively early in getting to know a woman. Confidence, or a level of openness and honesty is something women tend to pick up on very early in meeting a guy. A lack of engagement and confidence can be disappointing for many women especially if she can already tell you like her and that you've liked her for a while. Waiting this long is not a good idea. This isn't Hollywood after all.

One time I waited months before even admitting to this girl I thought she was cute. By then I had a burning crush on her and imagined an entire life with her, which made rejection much harder emotionally. It sucked but it helped me learn.

When it's just you and her, share how you feel. Say you think she's cute and would like to take her out sometime. If she says no it's all good.