It seems awkward to me to refer to the previous century that way until you're at least halfway through the next century. Even then, that's pushing it. Basically I think that way of referring to an era implies you're over, or at least fairly close to, 100 years away from it.
I rather meant how it sounds. It's in the "hundreds".
Two thousands.
Twenty hundreds.
"Early twenty hundreds" does kind of make it sound like we live in 2224 instead while "early two thousands" sounds like 2002.
I could have written it better.
I mean if your life started in 2005 and you didnt live through any of the 20th century, calling it the late 1900s seems totally reasonablr. You werent there when people were living through the "90s", to you its just another bygone era that people speak about in waya you'll never be able to relate to.