Question for British list members/school years

[Carol]

Carol earlier:
> 
> > Do British schools have a Year Twelve, or do students finish
school and start university (or get a job) at seventeen (sixteen for
those born in summer) rather than eighteen (seventeen for the
summer-borns) as in the U.S.?

Catlady: 
> Per Geoff, old First Year (First Form) is now Year 7. Which would
make Second Form year 8, Third 9, Fourth 10, Fifth (the OWL year) 11,
Sixth 12, and Upper Sixth (Seventh Year at Hogwarts) Year 13.


Carol again:

Sorry about that. I should have done all the math instead of only part
of it.

Year 13, huh? Our high schools end end (as you know, being American)
with twelfth grade, thanks to the first year being kindergarten, and
not, AFAIK, compulsory. Maybe it's like hotels that have no thirteenth
floor, or , at least, no guests assigned to rooms on the thirteenth floor.

BTW, are the terms "freshman" (first-year of high school or college),
"sophomore" (second year), "junior" (third year), and "senior" (fourth
year) used in the UK at all? I think that "freshman" (for "freshe man"
meaning "new boy") originated there, but I was once reprimanded by an
OuP (Oxford University Press) editor for using "freshman," which she
labeled an Americanism. I could have sworn that the term was invented
at Eton!

Carol, thinking that Trelawney would approve of the American system
for numbering school years