I know that the magical pie causes 6 days of gained maturity, but what is 144 points? what does it mean by points?

i think Points = hours.
6 days = 144 hours ~ 144 points
I'm not 100% sure though

Yep, Luxaea is pretty much right. Maturity is measured specifically in points - but since these points can only be known for sure if a pet is genetically tested, the age is given in days on the profile page.

You might know some of this already, but here's the whole breakdown:

Maturity increases by one point per hour - but egglings and hatchlings can be sped up by nurturing. Every 5 nurtures increases maturity by 1 point!

You can see a pet's maturity in the IMG code, at the end where it says "&maturity=###"

You can tell the pet's stage from the ###:
0 - 72 = eggling
73 - 215 = hatchling
216 - 647 = adolescent
648 + = adult

Thanks, I didn't know what to do with the two sitting around in my inventory