Squash, probably pumpkin type. Does not appear to have reached maturity

Squashes cross pollinate readily. Winter squashes of the Cucurbita maxima species are all similar enough that if they cross and you plant the seeds, you'll still get a good winter squash. But the C. pepo species includes many very different squashes (zucchini and all summer squashes, delicata, spaghetti squashes, and the bitter inedible ornamental gourds sold in the US) so if the seed came from a cross pollination of two different ones of these, it's possible the squash won't be very good to eat.

The only danger is if it's bitter, then it could be toxic. The bitter squash toxin is not a problem if you just eat a bite to test it, but don't "push past" the bitterness and eat a meal of it. If it's not bitter then it's not toxic, so it's safe to eat and the only question is if it's actually good eating. Give it a try!

Thank you, @farmerdill and @HighColdDesert. I got some older pictures from a cousin who visited us, when the pumpkins were still growing. When they got orange& dark green colors, I broke one. My mother tasted it, she says it has no taste and no particular smell. I guess I'll give it a try, roast some seeds ;)

here you have the photos made when they were "teenagers"

Have a nice day :)