Can I still catch em all?

Don't worry, dude! :) You most likely have 2 more years until the next batch of new pokemon are revealed. That should be enough time to get familiar with Gen 4 - 6.

And to answer your question in the title, it's currently possible to catch 596 pokemon in the National Pokedex. When Pokemon Bank is released on December 27th, the remaining 149 Pokemon will be available through transferring from Black and White (you can have someone to help you get most of the remaining pokemon through online trade). Getting legendary pokemon from previous games will be your only issue if you aim to "catch 'em all."

There are some you just won't be able to get, like Celebi, Deoxys, Arceus, and Victini, unless you've been keeping up with special events. I'm pretty darn close myself though. 460 or so on X/Y and I have a bunch on Heartgold and Black 2.

Thanks people! :) omg i am loving pokemon Y so far. I take forever to train my pokemon though. Like i spent over 2 hours in the same patch of grass at the beginning. I always feel the need to train a ton prior to moving foreword. I may overdo it a tad. XD

Glad you're having fun. The joy of playing a new Pokemon game for the first time is indescribable. I envy you.

@gamerguy1415: You get the exp all very early in this one, so there is really no need to grind...in fact even without grinding I found myself often too overleveled

Thank you everyone :D I just beat the game today, and I liked it so much, i think im gonna get pokemon X and play that too. How can i transfer my pokemon between games? I wanna have all my pokemon Y pokemon on my pokemon X. Also, can i do that with other versions like black, heart gold, diamond, etc? I eventually want to have all my pokemon on one game

Trading between multiple copies will be easier when Pokemon Bank is released. Pokemon Bank can hold up to 3000 pokemon and can support multiple copies of X and Y per 3DS. Simply store your pokemon to the bank from Y and then access the bank in X.

You can not transfer pokemon from Diamond, Pearl, Platinum, HeartGold, and SoulSilver (or any previous Pokemon game) directly to X and Y. If you want to transfer from those games to X and Y, you will first need to transfer the pokemon to the Generation 5 games (Black, White, Black 2, White 2) by using a second DS or 3DS, and then transfer those pokemon to X and Y via Pokemon Bank (second 3DS not required for the bank).

@ANIMEguy10034: Thanks! :) One more question, so i just ran into a wild Articuno and it immediately fled. I've been tracking the thing ever since, but every time i go to its location, its long gone. Someone told me that you must encounter articuno about ten times before it goes into a cave and becomes catchable. Problem is, i can't seem to keep up to this vulture.....

Oh yeah, those birds can be a huge pain to find.

Articuno flees from its area shown on the Pokedex map if you use Fly. I recommend flying to Lumiose City as a starting point since it is right at the middle of Kalos, check the pokedex map, and walk to Articuno's location by foot. It may take a while, but it worked for me.

Another method:

"You will need MAX REPELS and a Pokemon FIRST in your party lower than level 65, and later you will need SURF. You will need to get to Santalune city, once there spray your MAX REPEL. At this point it's up to you if you want to walk, run, skate or cycle but cycling on your bike is quicker. Head to route 4 and enter the grass to look for the bird. If it does not appear then go back into Santalune and then straight back into route 4, head back into the grass. Just rinse and repeat this since your bird will eventually run into you and sometimes it will happen in quick succession!"