Squashes readily cross-pollinate so if you have several different plants there is always a chance of fruit set even if one plant only has female flowers.
Butternut squashes are usually amongst the slowest to develop and ripen, although of course there are many cultivars bred to do better in our climate.
For most of us, it probably is getting a bit borderline for plants which haven't set any fruit at all yet, although the weather is clearly a factor, and I'm not going to try to predict that, especially this year!
You will have up until (just before!) the first frost for the fruits to ripen in situ, although I usually find the plants have pretty much died back well before the frosts arrive. Squashes which haven't developed a hard skin won't keep as well as those which have fully ripened, but they will continue to ripen indoors and will still be edible as long as they managed to grow to a reasonable size.