You need to tread carefully bringing up the subject... remember girls have the whole s*** factor to think about as well. Personally, I would avoid openly bringing up the subject of sex as (from my experience) it only works on three types of people.
a) Those who are promiscuous or work in the sex industry (e.g. strippers, camgirls etc.)
b) The kind of blunt girls, who speak their mind
c) Those who are extremely confident and assertive.
With other types, you risk scaring her off by implying this is all you're after... so ... "
down boy"
As other have said, I would avoid mentioning it in the texting stage... but if you really wanted to "
test the water", you could, maybe send a dirty joke (Caveat:- make sure it's female friendly) and see her reaction and go from there. If she laughs or otherwise shows she's OK with it, then maybe move up to a meet. If she goes silent (or worse berates you in some way) you'll know she's not ready and you leave it for a bit and carry on as you have been (if she'll still talk to you lol).
Even if & when you meet in person, I don't think it's a good idea to explicitly mention it... although it's OK to imply sex is on the cards by certain body-language and actions (e.g. wondering hands).
IMHO, this is coming on way too strong... especially for a first meet. I think it might be a better idea to start of with lighter, less sexually obvious touches before. Build up some intimacy by whispering something in her ear, and maybe lightly touch the small of her back to start with. Or maybe let her instigate physical contact... it's likely she'll do something like lightly touch your arm when you say something funny or endearing or remove an imaginary bit of fluff from your top. While kissing lightly touching her bum (
OUTSIDE her clothing) may be a safer sex than putting your hand inside her... if she lets you do that, then you can try a more intimate grope a bit later on lol.