Juerte, Ajuera
 

What people in Mexico say AJUERA and Juerte with jota?

Just to make it clear, I believe you're asking where they pronounce 'afuera' as if it were spelled 'ajuera', but with a softened 'jota' sound (making it more like the American English 'h' sound).

This doesn't occur only in Mexico. You'll hear altered consonants and, to a lesser degree, vowels just about everywhere.
I've heard that this particular phenomenon occurs in the coastal areas, but I believe it is more wide-spread than that.

The speech used in a particular region should be mimicked if you want to fit in.

This happens in the United States, where American English has several different flavors. Southerners definitely speak differently than folks from the Midwest.
The East Coast, around New York and Boston, have very different sounding words. I've heard people from New York say 'all' as if it were spelled 'wall' quite often, for example.
It's OK to adopt. The nuances in language from area to area make things fun!

I agree with Rusty.
Normally, this kind of pronunciation is commonly heard in less educated people all over the country, but it's mostly associated with some regional accents from the north.