Only one Person can give you an Answer to that: SheThe only person who knows for sure is her. Just ask!
Generally, as long as she is reciprocating and you are not the only one always texting first, its OK. But, you should really just ask her. What´s wrong with a simple: Hey - we text a lot. I kind of enjoy this, but please tell me if it´s too much, OK? or I´ve been noticing you toned down the texting lately? Are you getting tired of it? Do this in a personal conversation, like every serious topic - texting is only for chit-chat as you can´t adjust tone or read emotions through text!
Being open and talking about issues to find some common ground is the key to any successful relationship! (That´s at least to my own experience)