Accidental Dirty Talk too soon. Help!

I am such a nerd and a newbie when it comes to dating lol. I just turned 18 last weekend and just before that I asked a girl out on a date. Now, the way we met was through math class in college. We both got out of high school early and I asked her out after only about 5 minutes of talking. We met for lunch at a typical American restaurant. We ended up talking for about two hours and I felt really good about the whole thing. She had to go because she had volleyball practice so she was kind of rushing and I managed to squeeze in a quick hug. The thing about the relationship is that I just don't think she really feels anything for me. It's the strangest thing. Whenever I am with her (every math lecture Mon & Wed.) and I get to talk to her she seems so nice and seems to care somewhat about our conversation. It's just that when I am texting her she feels so much like a different person. I think that I just made a huge mistake. I think that because this is the second relationship I've ever had ( not sure if the first one counts, because we were friends first & I knew she wanted to be with me) I took it too fast. We have met up and talked twice. The first was the lunch date on Friday. The second time was about 10 minutes after class the following Monday. Today is Wednesday, right after Monday. She rushed out of class and did not wait for me at the door. I didn't mind because i had a meeting to get to, so I texted her later asking why she left so early. About three hours later she says that she had to rush to get ready for volleyball practice again. Slight banter, then i texted something bad. I knew I didn't want to send it but I typed it anyway because i thought whatever, but then my sister said something to me and I accidentally sent THIS exact text to her: "That's cool. When u talk about practice i imagine u hot and sweaty... Hott ". You know when you do something so terrible, that you die inside a little? WTF was I thinking!? I haven't even KISSED her yet! What should I do? have I lost all hope? Can this be salvaged? Help fast!