The average is about 6 months. But they all vary and it depends on how many times she goes in the house. The more accidents she has, the more that behavior is reinforced. So, you have to prevent accidents by super careful supervision, never taking your eyes off her, using her crate if you can't watch her, even if it's just for a couple of minutes. Literally, she needs to be watched constantly. It's difficult, but the more times she's reinforced (treats, praise, a big fuss) when she goes outside, the quicker she'll learn. Right now, she is very young and can barely feel it in advance and sometimes they get so busy playing, they don't feel it at all till it's coming out.
I don't believe in punishing a puppy for having an accident. It can cause all kinds of problems from a dog hiding it behind furniture to a dog being afraid to go in front of you to a dog who thinks it's a no no to pee at all and will hold it when they can until they can hold it no longer so they go behind furniture. Scolding a dog for going inside tells the dog that this one spot is bad, but there are many other possibilites inside which she might be able to go which are safe. Dogs see things as safe or dangerous, not morally good or bad. The more times she's reinforced for going outside, the more she'll want to try to go outside, she'll want to repeat that because that is where all the good stuff happens. One place to choose: outside. Not having to guess at which place inside (out of many) might work. If you catch her in the act, interrupt her, "Hey!"...maybe clap your hands and scoot her outside. But don't make her fearful or startled too much...just enough to try and stop her mid stream and get her out.
Some dogs take more or less time than the average. My Dobe didn't get it reliable till he was about 10 months old, other dogs have taken just a few weeks. So, be consistant, watchful and you can even keep a log of when she goes in relation to eating, drinking, playtime, nap time so you can get an idea when she's likely to have to go. But take her out often, at least every hour for now....even every half hour. Give her ample opportunities to be reinforced for going outside.
Good luck.