Pony Ages Solved
I like to imagine the ponies are roughly the same age as their equestrian girl counterparts. So that would put them in the age range of about 18 or 19.
However, I have a theory that in Equestria, ponies mature much faster than humans do, which means they could've been legally considered an adult at age 14 or 15 in pony years.
As for Spike the dragon, I like to imagine there's at least a 7-year difference between him and Twilight age-wise.
Because dragons can presumably live for thousands of years, Spike is still considered a baby in dragon years. In pony years, Spike is actually a teenager, which would still technically make him a minor.
However, in the later seasons of the show, he could be considered an adult because he could be old enough to be one in pony years.
However, I have a theory that in Equestria, ponies mature much faster than humans do, which means they could've been legally considered an adult at age 14 or 15 in pony years.
As for Spike the dragon, I like to imagine there's at least a 7-year difference between him and Twilight age-wise.
Because dragons can presumably live for thousands of years, Spike is still considered a baby in dragon years. In pony years, Spike is actually a teenager, which would still technically make him a minor.
However, in the later seasons of the show, he could be considered an adult because he could be old enough to be one in pony years.