Forget about expert, I have absolutely no clue what I'm getting myself into... however.
Honestly, you never know until you try. You're going to have issues. You're going to be awkward. So, then, might as well be true to yourself and be as awkward as you can manage. Stammer, breakdown, be honest.
Another thing is you don't know what the other side is thinking. But, if she knows you well enough and knows that this is difficult for you to convey, then it is likely that she will be patient to wait for you to make yourself clear. And if she is the friend you think she is, she will be honest and blunt with you. A yes or a no. Or even a maybe, let's try this thing and see if it goes anywhere.
Life is about chances. Anxiety makes those chances harder to grab a hold of, but that doesn't mean you shouldn't try grabbing them at all. Grab at them blindly. Cry. Wail. Struggle as you reach and grab a hold. Reach out and jump.
Nobody knows how to deal with these situations. And even if they do, they only know how to deal with their case, not yours. You are unique to yourself, and your issues are unique as well.
Go for it. Be honest. Mess up all you want. You'll never know until you get there.