Definitely soon. Do you have everything you need ready?
Lots of old towels/cut up T shirts, (whelping is messy, these can be thrown away as they get soiled) and face flannels or something of similar size to grip any pup that may get stuck and rub pups that are born 'blue'.
I would also have some KY jelly or similar lubricant on hand (obstetric gel is the best, you can get it cheaply from agricultural supply shops) again to help with stuck puppies. If you can get 1ml syringes, fill these with gel now, it will save valuable minutes if you do need them. You can then squirt them around a stuck puppy, often that is all the help the mum needs. Study how to help with stuck puppies, they are not uncommon in small breeds. You need to grip firmly behind the head and pull downwards towards mums belly when she pushes. If the stuck puppy is breech (feet first) I would pull it out ASAP, don't wait for a contraction. Breech pups can drown if stuck, but are actually considered a normal presentation in dogs, so expect a few pups to come out backwards.
Dental floss is the best thing for tying off umbilical cords, but these rarely cause a problem IME.
Have something with calcium in it to offer mum between pups. Ice cream is often used, as it is also high in sugar and fat to give her an energy boost.
Do you have an experienced friend who can be with you for the birth? Also did your vet give you any idea as to the size of the litter/pups?