She's young, you're going to get accidents I'm afraid. Certainly be diligent but definitely take her out every hour. If she doesn't go after a few minutes, take her back indoor.
There's a theory that using puppy pads is counter productive as they end up only going on those. However, I got so fed up with Millie having accidents that I tried puppy pads. She ignored them and still had accidents elsewhere
I was told by my dog trainers that a puppies bladder is late is developing control at 16 weeks, so don't be too hard her or yourself. She's only a baby. I was advised to clear up any accident with a biological cleaner to remove odour that may attract her back to the same spot. Not sure it worked, we still had accidents.
One day she did nothing but accidents and I was in despair. I goggled to see what I was doing wrong and I read a lovely piece by someone which went something like this....
If you puppy has an accident in the house, get a rolled up newspaper and hit yourself with it! When they are very young puppies its not their fault, its yours for not paying attention.
It helped me get my sense for humour back, clean up and get on with the job
As she got older, say 14-16 weeks she had the very odd accident as if she didn't mind going inside or outside!! A police dog trainer said that even if I find the accident some time later, I had to take Millie to it, hold her nose near to the spot and give a firm No and take her straight outside and give the toilet command. And of course give plenty of praise for actually going outside. I felt mean telling her off, but only had to do it a couple of times. She got the message.
I think puppies are like children, good at some bits of development, bit slower at others. Millie never gave us a disturbed nights sleep, but was a nightmare getting the hang of toilet training.