pumping at work

I don't go back to work until mid September, but I have been looking into getting ready to start pumping and working on building up a stash. The only thing I am confused about is pumping at work and the allotted time I will have. My DD nurses every hour to hour and a half during the day, two-three hours at night. Since most of her nursing sessions are about the hour to hour and a half span, and I am only allotted to nurse every two to two and a half hours, will that interfere with my supply or will I be ok? With my first DD, she weaned herself from nursing at one month. With my newest DD, I want to be able to EBF her until she is at least one year. I do not want to supplement if I can avoid it. Another question, did anyone's LO's nurse every hour to hour and a half ever end up going longer periods in between nursing sessions? I am hoping I can get her to go a bit longer between feedings before I go back to work. She will be just shy of 4 months when I go back to work.