@popcornhigh
I come from a middle-class family. I got into the Ateneo by accident--I wanted to go to UP but my dad didn't want me to dorm, and I told him it's either UP or AdMU (thinking that he'd relent and let me go to UP since we could not afford AdMU). He chose AdMU o_O
Anyway, I came in expecting all the stereotypes I heard about and expecting not to fit in. During the first few days, it seemed like all of my blockmates were like that. Conyo, well-traveled, very rich with their Louis Vuitton's and Havaianas. I didn't feel at ease with them, so I hung out with a grade school classmate and some English blockmates. Over time, I realized that my conyo blockmates and I had common interests (and a lot of those were about things girls from my high school would never have touched if not under pain of torture such as: books, comics, Japanese boybands, languages, etc) and their English twangs and manner of speaking dropped once I got to know them better. Along the way,
I picked up the Atenean vernacular as well--taglish. @.@
I can't tell you if Ateneo will be a great fit for you. But I can tell you, 100%, that those four years in Ateneo were the best years I've had--I learned a lot academically, I learned a lot about life and other cultures, I had a lot of fun--and I never expected that I would be as happy as I was then.
As long as you're open to new experiences and you keep an open mind and stay true to yourself, I think you'll be fine in AdMU.

Migz is right, an open mind is key--there are a lot of lessons in the curriculum that will shock and sometimes make you question your beliefs; then there's the people you'll meet. Just like any other school, students in AdMU come from different backgrounds--kids from the provinces, public high schools, private high schools, international schools, La Salle, true blue Ateneans etc.--the only difference is that students coming from families in the higher bracket of income is the norm and not the exception.