Need advice on a tricky situation with a friend?

I met a girl several months ago. We hit it off very quickly - we share similar senses of humor, lifestyles, etc. - and became fast friends.

We have shared a lot with each other, things like our personal struggles and such, and have been very supportive of each other throughout our friendship.

A couple weeks ago, she mentioned to me - while I was lamenting about a situation that didn't work out with another girl - that she would gladly be willing to date me if she didn't have a boyfriend. (Now, I do not have any experience being in relationships, or even the small stuff for that matter. Not surprisingly, I was taken aback by it.)

I laughed it off and things continued to go as usual. When I asked her about it later on, she said it was because she thought I was a great person and that we're a lot alike. At the same time, she said that she would likely be separating from her boyfriend due to grad school and wasn't sure that their relationship could endure that.

I have been very respectful of their relationship, and ask next to nothing about her with her boyfriend (because, obviously, it's not my place to do such a thing). After talking to her about it since, I've found this out: we both genuinely believe we would be great together, but I'm a bit unsure about it.

I feel semi-stupid for asking this, but am I just a third wheel or an option to her?

What should I do? (I'm considering letting things be and having the chips fall where they may)