There are 2 types of dentures you can discuss with your dentist. One is called immediate dentures where they make your dentures before your teeth gets extracted. After your teeth are extracted, the dentist will fit the completed dentures. The disadvantage is that the immediates don't fit as accurate due to the changes in bone and gums after teeth extraction. After about 6 months of mouth changes, the denture may be relined but may still have limitations. You may have to consider a new denture depending on how ill-fitting it is.
The other type of denture is waiting until all of the mouth changes are stabilized after 3-6 months to fabricate the denture. This type is definitely more accurate and better fitting. But you will be without the denture until it gets fabricated. You can consider doing both which is double the work and cost.