Before you all say "going into x", it just doesn't roll off the tongue very well, and it's not really what I'm asking.

a future freshman into college

._. See above, Archer.

Once You Go Back To School, Before then you say ur staring grade "x" after the holidays. Right?

This is confusing

I started school in Kindergarden and I am in 12th grade

Uh, thanks for the info, Archer...? o-o
Anyway, yeah, I thought this might be the case, but more what I was asking: in the middle of the summer holidays, what grade are you in? Or are you in a limbo between? Probably the latter. I think I have my answer though, so thanks everyone :>
(even though I specifically said "don't answer with this" and two of three people answered with that >_> )

You literally asked for it lol

I asked you at which point one calls themselves by their new grade, not how long you've been in school

This is so confusing :baw

Once I've finished and I'm on my summer vacation I say "I'm going on grade #" and then when I start school again I say "I'm Grade #"

Seems confusing where you live. In France we aren't a grade, we just say we're in grade X, at anytime we're studying said grade. And in between, during the summer Holidays, we used to say we are passing to grade X+1 (or stay down in grade X).

I do it during summer holidays