I'm not sure how to explain this because a lot of people on here will just chalk it down to rudeness, or laziness because they simply can't understand but I am one of those people that takes weeks to text back and it's not down to either of those things.
Personally I struggle with any social interaction, it takes an awful lot of energy for me to have a conversation in person or on the phone. If some texts me after work, after 8 hours of forced social interaction, you won't get a reply until I've had time to 'recharge'. And if that text is sent on a Monday that might not be until the weekend, and by then I may well have forgotten I even read the text.
It is a physical exhaustion that I feel when dealing with anything social, and just because "it only takes 2 minutes" doesn't mean anyone is entitled to anyone else's time.
That being said, I do make the effort to respond to important or time sensitive texts, for example details regarding meeting up, despite how it makes me feel.
My friends and family are very understanding that this is the way I am, and I am not devaluing their time, nor do I think less of them or the relationship but I am very open with how I am. And I know that this sort of thing affects more people than you think.
It might be worth having a conversation with her when/if you do meet up and see if this could be the case here, instead of just immediately writing her off as rude.
If it's not the case and she just can't be bothered then don't bother with the friendship, but you won't know until you actually speak to her.