Girl I like (a lot) just entered into a relationship

I'm 30-ish, she's 20-ish. We've been attending the same 'exercise' class for about 2-3 years. I could tell she liked me almost from the start, and although she seemed nice, I felt the age gap was too much, and like I didn't know her well enough to reciprocate the same interest. Also it just wasn't a good time for me.

Then she got into a relationship which lasted I think about 12-18 months. She was very intentional about not sending me 'signals' while in the relationship, which I respected. About 9 months ago they broke up. She didn't resume her interest in me immediately, she took some time out to herself, which I also respected, as I don't tend to like people who look for rebound relationships or sex. She showed slight interest in me again in June, but then we went our separate ways for the summer, and resumed our classes in October again.

I felt she was of a more appropriate age by then, and that I knew her better, so we flirted a little. But I've historically always been slow and even 'clumsy' at making my feelings known to women. We had a social gathering at her place about 2 months ago, where we flirted quite a lot, and it was really enjoyable and easy-going actually. But I waited too long. She got together with another guy about a month ago. I don't know all the details, but suspect she'd been seeing/talking to him since about September-ish as well, and figures that he is a more 'reliable'/straight-forward option than I had been to her. I found this out on New Year's day, where we all met at her place again. Yet still, I saw signs that she probably is still attracted to me, even though she tried not to show it out of respect for her new relationship.

I did not expect it to sting as badly as it did, seeing them together. I met the guy, and he's alright. I don't have issues with him. My only issue is that I feel I missed out on an opportunity for a relationship with a great person. I rarely feel this strong about someone (and maybe that's my problem - I don't know).

So I'm now torn about whether or not to be direct and make my feelings known to her, or not. I have no intention of pressuring her to quit her relationship. I want to respect her choice. But I'd also like to get this off my chest, as I feel like both me and her have suspicions of what each other are thinking, but neither has the guts to say it, which leaves an awkward 'elephant in the room' that gets in the way of our conversations now. It's bothering me a lot. I'm looking for a 2nd opinion.