Aesthetically, I love all skins, all sizes (unless we're talking about extremes), all colors. Age, anything between 18 to 50, usually the best to me is around 30 to 35.
Actually, it changed a bit regarding younger women, the more time goes, the more I'm put off by them. The immaturity rubs me the wrong way, and when there's a mix of infantilism and young age it just makes me feel nauseous. There are only a few exceptions in porn, usually people who display at least some amount of emotional maturity.
Petite women gooning to dildos and vibrators who show lots of feet are my thing lately, and for some reason I get off more if they're darker or black.
Back to the age thing, I wouldn't date someone below 21 in real life. I
would be open to dating someone older, but I've given my share of that already, I would like someone my age or younger at this point.
I noticed that I don't exactly have a single type in real life either, I like all kinds of women. In real life, I tend to be attracted by petite tomboys for some reason. Usually they're incredibly hot women who want to fend off unwanted looks by attempting to look more manly (and they're probably lesbian-bi)... it's ironic that they only get my attention a lot more, I love that contrast. There are two who live in my neighborhood, and I see them often on the bus.
EDIT: I forgot to answer whether it changed over time. Uhm... other than the age thing, inevitably, my porn tastes have gotten more hardcore. I still don't like eccessive violence, I still don't like dirt taboo bullshit. I used to watch more white women and Japanese porn in the past, now my tastes comprise all women of all kinds. Am I more racist or less racist now?

I should thank porn for making me consider dating a black woman or an asian woman in my city? They're not very common where I live.