esim purchase and set up

Hi all,

I have just used the T Mobile esim app, to purchase an esim.  I filled in all the details etc, although somewhere I read it would ask when I wanted the esim activated.  It is for use in an upcoming trip to the US. There was no such request about when you want the esim acivated.  I read that the esim would not be able to activated until I was physically in the States.   Well here I am in Australia with an active esim.  How do I fix this and why did it activate if I am in Australia????