uhm, Im kind of pissed off no one on this forum has given you the information you need. Txting, calling her blah blah blah..... all that sh1t doesn't matter.
The reason she might be LOSING INTEREST is because you are not giving her your PENIS!!!!!! Plain and simple bro.
YOu talk about this girl being old fashioned????? ...... What kind of old fashioned girl brings a guy home on the first date??? ....... She is of the NOW, she is a women who wants a MAN to take control of her...... I mean C'mon man, she has given you three, THREEEEEEE chances alone with her to Bang her and you haven't. On a primal subconscious level women take this as rejection and pull away..... Do you think girls just like bringing guys back to their house, make out and then be rude to them by not txting back??? NO, they're only pissed when they don't get satisfied...
She has basically put it all on the table by inviting you over, and you didn't LEAD HER INTO SEX!!!!! ..... Its not like the movies where you go to hers and she rips off all her clothes. ITS NOT!!!...... ONce you guys hint at it, it up to YOU to progress with her and lead her into SEX. Even though she may want it more than you , she won't be the one who escalates. Its a MANS JOB.
I recommend you read VIN DE CARLOS ESCALATION LADDER. It will teach you how to Escalate properly which you clearly need.
Sorry if I came down a little hard on you bro, But I think you needed a little slap in the face to get your head back in the game....