Well, understand that "experience" consists of screwing up a LOT.
Rule of thumb is, ask questions and let the other person talk as much as you possibly can. The soul of being a brilliant conversationalist is remaining engaged while other people talk about themselves. Not just women, but everybody. Going on about yourself unbidden comes across egotistical and shallow. Giving other people permission to go on about themselves indicates you find them interesting. If you can have such a conversation without being bored to tears you've probably struck a good balance and should ask for a second date.
Back to Henry, I've got to agree with the consensus: you're about to gain some of that experience I mentioned up at the top there. Here's the thing you really need to get through your head: you're thinking of yourself as a "nice guy" here, but your actions are not very nice at all. You've lied to your friend to keep him from asking the girl out, and then you've lied to the girl by focusing on "just friends" when that's not what you mean. You're doing a lot of lying to protect your own feelings while at the same time steering people into behaving the way you want them to behave. That isn't nice. It's manipulative.
Listen, Henry, what you're going through right now never, ever gets any easier. We can't tell you anything that will make it so. In fact, in many ways it gets harder as you go on, because the people become more complicated. Try figuring out how and when to approach someone who has recently been through a divorce after several years of an unfulfilling marriage, where "I need more time" likely really means "I need more time." Now that is tricky.
The only thing you can change about the situation is yourself. Being confident in this situation is not about lack of nervousness or uncertainty. It's about acting with integrity despite being nervous and uncertain. Acting in an adult way here means owning up to your own feelings and needs without expecting that other people are obliged to indulge them. Be quick to take responsibility for what you want, but slow to get hurt when things don't turn out in your favor. Sad to say, you are doing exactly the opposite here. You're trying to figure out the right thing to say to game the system so things turn out the way you want them to with minimum risk to yourself. You'll have disappointing results until you figure out not to do that.
I just wanted to be the 177th person to quote you.
Good advice for all of us, even the guys who think they know what they're doing.