SO back when Mass Effect was released, I played it and really liked it. I got a little farther than the part where you rescue the blue woman, Liara is her name I believe? ANYWAY, I traded it in back then stupidly, and tonight I grabbed it again for 15 bucks because I need a new game to enjoy. So my question is:
 
Should I resume from where I was and be confused as to what's going on, seeing as I don't remember ANYTHING, or should I begin a new save file? What do you guys think? Also, how far along was I in my original playthrough?

It depends on if you did any of the other available missions off of the Citadel before rescuing Liara.  If rescuing her was the first thing you did once you left the Citadel, then you should be okay going back with your old save.

Just start over, it's a great game.

That's about where I am and I don't think the story has progressed all that much yet but that was the first place I went so I don't know what happens on the other planets, 
but if you went straight there you should be fine.

" @CitizenKane: Is there any way I could tell by I dunno, looking at my achievements maybe? (that's not sarcasm by the way, but it sounded sarcastic when I typed it) "

I would start over or read a walkthrough of the parts you don´t remember, that way you will know what is going on.

" Just start over, it's a great game. "

Ok, I loaded it up and I remembered what had made me stop playing the game in the first place: an insanely hard boss fight with **SPOILERS** Liara's mother***SPOILERS*** that I couldn't get past. Should I still start a new game?

**spoilers** kill all the reinforcements that spawn immediatelly when they enter, when y're fighting mom. And make her immobile as much as possible (floating in the air and stuff) **spoilers**
 
But y can start a new game anyways. It's a great story. Maybe you can do things a bit different from the first time to see what happens!

Does anybody happen to know if  you can restart with exatly the same looking character? Without having to remake him.

Dude I'm in the same boat you are, I just bought it back, I really need to start that game over.

" Ok, I loaded it up and I remembered what had made me stop playing the game in the first place: an insanely hard boss fight with **SPOILERS** Liara's mother***SPOILERS*** that I couldn't get past. Should I still start a new game? "