Hi!
I'm new too, but I'll offer a nickel's worth of observation, if it helps...
You strike me a pretty analytically savvy, so you are probably used to self analyzation. If this is at all true, you should know that time and time again I have been sternly warned against doing this. It cannot be done objectively.
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A concrete observation you made is that while you oppose being too cozy with this person, wish to respect her privacy by not letting her know about your feelings (which is perfectly appropriate and actually quite considerate), you have had this type of idealization, as you put it, before with others, only to devalue them completely when you finally gather enough information to apparently realize they are in fact human. You could ask yourself why this seems to happen repeatedly. Professional guidance sounds like a good start. Trying to discover what you are searching for in others to help you feel some sort of fulfillment seems as good an investment in discovering your own well being as any
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I'm going to throw you one curve ball though, and please think seriously about this. You have some sort of morale opposition to having genuine feelings for this person, and apparently this is something that elicits strong emotions for you. If you are refusing to contact someone because you fear you are falling into some state of love for them, are you now being considerate to them or are you simply avoiding getting close out of self protection? Do you simply resist the idea of being gay, or Bi for that matter, out of a moral standard and refuse to consider alternative perspectives on the subject? You need not be gay to love another human being. And discovering that you can have true and deep fondness for someone without putting them on a pedestal or idealizing them would probably be a lot healthier and less lonely than isolating yourself from any relationship that pushes your comfort zone. I hear your judgement of your former heroes, and coincidentally your judgment of your own feelings, to the point of isolating yourself from a potential long term and valuable friend for years. Even the rest of your lives. I'm not saying to do anything that you find immoral. I am simply suggesting, gently, that some of the restrictions you are placing on yourself may not be for the benefit of others as much as it is to protect yourself. Who knows? You may grow to love this person tremendously, and you each learn to become a source of deep strength for each other in times of need. It is perfectly acceptable, and personally I consider it healthy, to love your close friends. Don't you think it callous to not love your friends?
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I know, you are indicating that this feels like an inappropriate fixation. Again, I will gently suggest you dig a little and ask yourself the truth. Are you simply morally opposed to being attracted to someone of the same sex and refuse to allow it to be considered by your mind, or are you...honestly...finding yourself physically attracted to this person, and are disappointed with yourself for feeling this? This could explain the disenchantment with heroes of the past, and the recurring fascination of a new idol. Pretend that you must be totally honest with yourself and ask the question directly, from different angles, until you are either sure you are NOT gay (you will find you are comfortable with this knowledge), or you are sure you cannot say for sure. Either outcome is a success, and a good place to work from.
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One last thing...whatever you judge yourself over....whatever it is....gently...give yourself permission to...forgive yourself for being human...whatever it was...it can be forgiven..

You might even discover that you have a whole side of you that has been hidden from view, and is totally lovable.