What does your seed package say as to the days to maturity.
Pumpkins can take from 70 to 120 days that's 2 1/2 to 4 months. Now that's growing time not time in the field with the plants half dead and the pumpkins ripening.

If I were you I'd think about buying them this year and planting them in spring nrxt year

Another thing to consider, the days mentioned on the seed package are probably for ideal conditions and ideal weather. That is, a 70 day pumpkin may take 100 days in a cooler climate. Here we have frost by the end of September but I find that even by the first week or mid September the weather has cooled off and plants like cucumbers, melons, and pumpkins, though still alive, aren't really putting on their best growth in the cool weather.