I'm going to take the mantra of my good friend Tropics here "There's no such thing as failure, only feedback"
You may have missed an opportunity, I don't really know, really tough to say. Wait 2-4 days from the last interaction and when a good option presents itself you can try again.
If you are going to open cold, try something stupid and funny and random, maybe alluding to an inside joke.
Keep in mind, you didn't lose anything here, you guys are where you were before the conversation or possibly slightly ahead.
I will note this isn't quite what I mean about the push pull. I will use a concept I think David Deangelo came up with (one of the few great ideas I do like from him), Two steps forward, one step back.
It would be more like, say theres a spark when you're together, you gently pull away so she ends up kissing you. You guys kiss for a bit, hands moving everywhere, then (huffed with energy) you pull away and say somethin like "what are you doing to me girl", etc. All stuff to pinn everything that happened on her
Think of it, if you were the one who pulled away when you guys almost had sex, she'd be like WTF? Preferably you do it in a few steps cuz then her momentum keeps rolling
I am guessing she would have accepted. But if she really really wanted to she could have asked you too. Maybe she was secretly hoping you would invite her? Who knows, if she was tho, that desire will be stronger next time, so I wouldn't worry about it.
The game is all about risks, I still face rejection or hot numbers that grow cold all the time. If you think through something and it really seems right, go ahead and try it.
My most important advice to you however is that you start networking more, talking to other girls, working on other options.
Even if this was the girl you wanted forever, talking to and flirting with other girls has a drastic effect of helping your game with her. It just makes you more confident, more comfortable, and less worried about what happens, and better prepared with how to handle everything.
Its wierd, but it just helps.