They are living things so they are somewhat unpredictable. Anything can happen, so don't be surprised if she does something unexpected. It depends on how strong her hormones are acting up.
With the disclaimer out of the way, most broodies will stay broody for a very long time. I really don't think chickens can count days. What I'd suggest is to wait at least two days and nights to make sure she is serious, especially if it is her first time. Give her a few fake eggs to keep her interest, but do not give her any eggs you don't want to lose. If you are going to move her, move her as soon as possible, preferably at night and with as little light and commotion as you can manage, then wait two days and nights to see if she has accepted her new location. If you need detailed help on how to move her, search or post on this forum. If there is anything people on this forum can do it is give advice.
After the two days and nights are up and you are sure she is serious, you can slip the fertile eggs under her. If you are going to order hatching eggs, start talking to whoever you are going to get them from to be prepared, but don't order until the two day are up, especially if you are going to move her. I know the weekend is coming up, but if she is really serious, an extra day or two won't really matter. Of course you can order the eggs earlier but you take a risk of having to eat them instead of hatching them. Kinda depends on how impatient you are. I know it can get exciting at times like this. I'd recommend getting fertile eggs locally if you can. Shipped eggs normally don't have as good a hatch rate as eggs that have not gone through shipping.
I'll give you this link, realizing you may not need it. It might be helpful.
Isolate a Broody? Thread
https://www.backyardchickens.com/forum/viewtopic.php?id=213218
Good luck!!!