Well, I'm definitely no expert, but another point of view could prove useful. Okay, so you two got some attraction going, and I don't see a big problem here, apart from your impatience. What can I say man... try to be patient, try to think of her putting you off by saying she's tired, etc. as a test. It looks to me like she's playing hard to get, seeing as she teased you with making out and now this cold shower. My advice to you is ride it out, be patient... if you want more from this girl than just sex. If I were you, I wouldn't have said "would you like to do something earlier?", but rather rescheduled for later (in my opinion one seems less hyped about the date, so that's kind of a neg). If you want this girl as your girlfriend, you should prove yourself supportive and understanding, and not just obsessed about seeing her (I know the wait is a motherf*cker... but that's just how things work). So invite her to this party, but don't put too much pressure on her, make it casual, make it seem like you aren't overly hyped (basically, return her level of interest). Oh, and about the texting, I wouldn't come out just saying "I've been thinking about you", instead, try to find some excuse for texting her, but along the same lines, like for example "Hey, I was at my moms house today, and encountered a flower that smells exactly like that killer perfume you had on that night, so if you could point me to a store that sells it...
or you could put it on again for (some event)" In my opinion that's less corny than just saying you think about her, especially if you insert some humor. Like I said, I'm no expert,veeeery far from it, but that's my take on this, so I hope it helps. At least a little.
Peace