I do this for a living. I board dogs in my home, and it's really successful. I've been doing it for 13 years.
There's so much wrong with this, so I'll give you some advice for next time.
Firstly, YOU should have gone to her home with your dog. That way you get to see where your dog will be spending it's holiday, and she gets to assess what her (territorial dog) will be like when you bring your dog in, and she also assesses whether your dog displays any aggression when it's put in amongst other dogs. This meeting is FREE and at the end of it, you'll be booked in, if all went well. She would also be asking you lots of questions at this meeting, such as:
How many meals a day the dog has
If he/she is on any medication
What is their chip number
Where do they normally sleep
Who can she contact if there's an emergency and you are incommunicado
Which vet is the dog registered at
Is the dog insured, and if so, with whom
I could go on......
You would also need to sign her Terms and Conditions. And show her your dogs vaccination card, to prove jabs are up to date.
After this, a trial date would be arranged, where you would leave the dog with her for a half or full day, for further assessment of what the dog is like when you are not there. You would pay the going rate for this session, as the dog is taking up a space.
I see in one of your posts, that you didn't check if she was a Registered boarder. This is a huge mistake, quite frankly. Registered boarders have to fulfil a huge set of requirements, to make sure they are suitable for dog boarding in their homes. Things like :
Secure garden with high walls and bolts on gates
Full medical kit for emergencies
No children under 5
All electrical cables tucked away
Food stored correctly
Medicine stored correctly
Access to fresh water at all times
Eating bowls clean
Own front door (ie. non main door flats not acceptable)
Boarder is registered with a local vet for emergencies
Floor is cleaned regularly with anti bac cleaners
Garden is clean and fresh (no dog mess left lying about)
A spare room to segregate a sick dog to, to stop the risk of infection to other dogs
Photo's of all the dogs vaccination cards, showing jabs up to date
Full pet sitting insurance in place, so if a dog has an accident, the insurance will cover any vets bills
All documentation up to date
Fire evacuation plan in place
My Council visit me every year, and check all of the above, and I am then given a certificate, which has to be displayed in my house.
By using a non-licensed dog sitter, you risk using someone who hasn't got a clue what they are doing. They often take unvaccinated dogs, exposing your dog to disease. They can have a garden with a low wall, that dogs can jump over and run away. They won't have insurance, so if your dog has an accident, resulting in a hefty vet's bill, then they won't cover your expenses. One time, I was walking one of my dogs and he cut himself on a jagged gate post - the bill was £1000, which my pet sitting insurance covered.
In addition, unlicensed sitters can leave your dog alone all day - you said the lady you met was at a party all day - who was watching the dogs? Licensed sitters are permitted to leave dogs for 3 hours max (which I never do).
The fact that you didn't see her home is a huge red flag - I know of someone near me that was collecting dogs, and they were sitting all day in crates waiting to be farmed out unlicensed homes. You must always see the boarders home and ask for confirmation that that is where your dog will be staying. They should have a facebook page showing lots of photo's of their customers dogs in that setting.
This was long, sorry, but PLEASE only consider licensed and insured dog boarders. Your council can give you a list of them in your area, or you could try looking on the good dog guide (on-line).
Contact them a year before your holiday (I know you couldn't this time) because a good boarder will be booked up well in advance. Personally, I do not take on any new dogs, because I am fully booked all the time, but you can ask to be put on their waiting lists.