Multiple ladies needing pump room...

Hello Ladies! So this is my first time having this issue. With my first two babes, I was always able to find an empty office if not my own, since I shared one for awhile. And no one else in my office was pumping during the months I was. But now that I'm at a new job, and theres a specific lactation room, I'm not sure what to do...

I had my youngest in Dec 17, and came back to work in Feb, since that time I've been pumping twice a day, around 10:40am and 3:40pm. Theres a number of women who are due soon with their babies, and most that I know, plan to pump. One women recently returned from leave, another will return soon too. But the lady who is back now, has been pumping during the same time I have been going. Not too concerned with not going at the exact time that I had been going, and I dont assume that she KNEW that's when I was using the room, since we really dont know or work with each other. My concern is now I'm wasting some time, twice a day going to the room, only for it to be occupied. It may not be more than a few minutes, but having to do this then twice a day, time will add up having to walk back to my desk and log back on, just to check a few minutes later? I dont sit close to the room. So my question is, how would/have you gone about handling this? Obviously I know she deserves to be in there just as much as I do, but I dont want either of us wasting our time waiting for the other to done. And then there will soon be more ladies needing the room too? Should I talk to her about my scheduled times? I'm not one for drama, and I hate confrontations, even though theres really nothing to "confront" about, I just hate going up to people, especially ones I dont know, with issues I have. Yes, I am THAT backwards lol I'm not mad, i know we'll all need time, just not sure how to go about addressing it. Thanks for any input!!