She's given you hope in saying that you might become a couple. Take that to heart and don't ruminate or obsess over the fact that you're not yet. The relationships that are worth it are worth waiting for. Rushing into being exclusive and as you call it "official", is just asking for heartache, especially when right now she has made it clear she needs time. Give her that time. If you truly care about this girl and want to be with her, then without question, this is what you should do. Be patient!!!! She likes you, everything in what she's said, makes that clear. Her reasons for hesitation are not to do with you, but that she needs time. After all she kisses, hugs, cuddles with you and obviously likes your affections. focus on those things and continue as you have been.