I can be charged with rape??

ok, my girlfriend has started sending me sexy txt messages. things like ' I wish I could show you how much I luv u' and 'I'm ready for sex, are u?' Just to get this out of the way, I'm a gentleman, I would never pressure her into sex.

I'm 16 and she's...

15. I'm worried about 2 things.
1. Is she really ready for sex, I don't want her to regret it afterwards
2. I've heard that parent can charge me for rape even if we BOTH agreed to sex, is it true?

it depends where you live, here it's if the person is under 18 and the other person is 18 or older.
and she may not be ready, it's something to be talked about and contemplated good and hard, and even sometimes you still regret it after that, think it through, don't rush it.

If you're both minors, then there's no crime.

What about the age of consent thing? most states are 16 shes only 15

If she's under 16 then yes they can prosecute you. Even if she says it wasn't rape...statutory rape is not a rape that's forced, it's sex with a minor.