Yes. The scores aren't bad so much as they're not particularly good. They're barely skating by with those scores, but a 2.0 will still let you graduate at most colleges.

GPA stands for Grade Point Average. Assignments that score 90–100% get an A. 80–89% are Bs. 70–79% are Cs. 60–69% are Ds. Everything below that is an F. Don't ask me what happened to E. I don't know that's just how it is.

Your GPA is a reflection of your average scores for all your assignments. Usually people mean GPA to refer to their cumulative GPA from all of their classes, not just one. A 4.0 GPA means you average an A on every assignment. 3.0 means you average Bs. 2.0 means you average Cs. 1.0 means you average Ds. 0.0 means you average Fs. So a 3.8 GPA would be good because it means you're scoring As and Bs on your assignments. A 2.0 would not be great because it means you're consistently averaging Cs (either lots of Cs on assignments, or lots of Bs and Ds averaging to a C, or some combination like that).

It's possible I messed some of this up because this is stupid and confusing and needlessly convoluted, but the tldr is that yes, a 2.0 and 2.1 GPA are not particularly exciting. That said, Cs get degrees.

Yes.

Then again some highschools including the public ones sometimes decide they will calculate GPA differently to be unique and quirky.

Like that time my highschool decided they will calculate it unweighted and out of 3 instead of 4

I jad to convince colleges I am applying that 2.8 is an average sized GPA.

(Weighted GPA means if you are taking a course like advanced physics, they will count it slightly higher to make GPA fair. Since people taking normal physics would have better grades while learning less otherwise)

Pretty much, it goes on a scale from 0-4, if you have a 4.0, you only have 'A's in all of your classes, if you have 0.0 you've failed all your classes.