Oh no! A girl is upset! Whatever shall we do?
Buy her candy and flowers!
J/K GP, J/K.
My serious girl advice? Don't listen to the group consensus, and make your own decisions about who you are interested in your love life. I browsed over the initial part of what you wrote, though I've read it before, but this time, I noticed that you mentioned your fellow employees all thought the girl you should go out with was Ada. Trust me when I say that listening to people for advice on who to date doesn't work, because the person who knows you best is you. So far, I've had three relationships that other people have suggested I be in, and the first two were terrible. The third was a little bit more successful, but mostly because I took my time getting to know her better first, and she was head-over-heels for me. The relationship degenerated pretty quickly, though, partially because a lot of the people around me pressured me into it sooner than we should have gotten together, and she wasn't prepared to contribute to a mutual relationship. As it turns out, one of the people guiding me into most of these relationships was actually using me as a scapegoat to avoid admitting that he was homosexual. He would focus on trying to set me up as a way to divert attention from his dating life before he came out.
The point: Make your own decisions when choosing who to date, and the speed that your relationship travels. If you take advice on healthy relationships, get it from those who are in successful relationships that you admire. By this, I don't mean hints on good dates, or dating tips and ideas, I mean what kind of person you should look for and who would make you happy. If someone attempts to coerce you into dating someone you aren't interested in or only are a little interested in, just take your time and do what you feel is right, not what he or she suggests. That's my 2 bits.
Oh, and if someone is in a happy relationship, don't mess with that. It just causes extra stress for the couple, and could really screw with their happiness.
Also, you seem too infatuated. Try to imagine what a relationship with Ada would be like, and you'll probably see that it would be nothing special, that you're just caught up on a girl you can't have. I think most of us have been through that phase before, and the sooner you realize it, the better off you are. If you dwell too long on the girl, it really could affect your outlook on a whole lot of things.