Bro, you've got some things wrong. You filled your head up too much about DJ's and AFC's. What a killer date that sounds like! You are the man!
But why did you water it all down? Making out in the backseat? Looking at the stars and cuddling? You just PROVIDED what every girl wants. You made her feel safe. That's a very good thing. She digs you a lot. There's evidence:
1. she didn't want to go home "so soon."
2. she asked if she was your girlfriend.
You landed her. Stop the fog in your brain my friend. That was a great FIRST DATE. Ask yourself this question:
Do you want her for her p-ssy or for all of her? As in long term.
Now that you have your answer, you should look back. Either way, you would've gotten it but you pushed insecurities back into her mind that every girl feels. This is why she asked "do you want me for just sex?"
Don't aim for that all the time. Aim for FUN. Not to lose your virginity or add another girl to your list. You got the skills, I can tell. But your mindstate is messed up.
And "just talking" is not an AFC thing to do, when you're trying to test a girl out for long term. In a guy's mind, we all want that, don't we fellas? After all the ass, after all the sex, deep down, we want someone we can settle with. Talking can actually help you buddy. Find more stuff out about her. It seems like you spent the whole date just trying to get laid, and not finding out about her. You learned your lesson. Always carry a condom just in case. But you overlooked her in my opinion.
When my girlfriend asked me if she was my girl. I dug her a lot. But real men don't blush, bat their eyes and say "oh yes, I am your boyfriend, hee hee hee." No, unless you want to look retarded.
It was more like this:
Her: I'm confused. We've done so many things, but you've never asked me out. Are we just messing around or are we boyfriend and girlfriend?
Me: (chuckling at her and shaking my head, lays hands gently on her shoulders, looks into her eyes, kind of like I can't believe she's asking that question) If we were just messing around, do you think I would be spending 2 hours with you every week? (lets go of her shoulders, turns around and continues walking)
I'm telling you, just as I turned around, she looked so confused. After two seconds of walking away from her, she ran up at me, and gave me a hug, almost crying. Can you believe that? Just from my delivery, she had tears in her eyes.
Don't pass up opportunities. I liked my girl from the start. Easy to talk to, but I still saw other girls just in case she wouldn't fall through. After a while, I knew she was mine. We had sex 2 weeks after the incident I explained above. Now we've been going out for about 2 years and we give it to each other on a daily basis.
It's a beautiful thing really. Don't pass up a great and fun time just because you didn't doggy-style/pile drive her. It will come, just as long as you have her locked on you. Hope this helped, because I spent some time writing this out for you.