To much Texting ??

i 've been chatting to a girl who i had a brief relationship with. We have been sending messages to each other for the last 3 months or so.. we have decided to meet just as friends and kind of see what happens ( thats how im looking at it anyway ) ..the problem i have is that now we have agreed to meet, which is in about 3 weeks time, i don't know how often i should text her, i dont want to screw anything up in these 3 weeks by over texting ect.. i'm aways thinking to myslef that she will probly meet someone new in that time, or she has'nt responded to my message which means she has changed her mind :p i know this sounds a little crazy, but she meant alot to me, i mean we only had a short time together but it was more than enough to love her.. I'm in danger of being hurt and rejected but i can live with that.. my real question is ...now that we have decided to meet up in the middle of next month, what do i do until then, im trying to get into really good shape and all that stuff, but how often should i send her a message whithout being too much?? im just trying to be cool in this time, but its not working

is texting a friend once a week ok ? once a day?

sorry for my spelling!!
please somebody tell me to be cool, i need to hear it