Until I read about her texting you, I suspected she may've been avoiding you. However, getting in touch at odd hours "just to talk" can indicate several things: she could want to talk and may genuinely be busy the rest of the time or she may even be, gasp, shy-- thus texting at hours you may not be up and immediately responsive. Either way, if it sticks to texting and talking long into the night, you face the distinct possibility of turning into her confidante and planting yourself firmly in "friend territory". Try to make a date ASAP. If she makes an excuse, be a bit persistent. Suggest she let you take her out for coffee or dessert after her plans. Something like that. Just be sure to facilitate some meeting. Once you try accommodating her clearly very "busy" schedule, if she's still unwilling to get together, give it up. She's either uninterested and, hell, even if she is interested, she doesn't value your time and efforts because she's evidently not making any effort of her own to try and change her plans.