Actually it can :P, cause you cant just "try", you will have to learn a TON of stuff before even attempting cgi, first you'll ofcourse need to know the basics and tricks of the program itself, then you'll have to spend hours and hours, honing(sp?) your skills in making an organic model ( humans), THEN you'll have to learn animation, texturing...etc...

Then you'll need to be able to make a good High Res model ( high poly in industry terms ), then you'll need to learn the actual CGI rendering effects etc.. and then finally, you will be able to make a cgi movie :P.

Thats why people follow courses or go to school for it, and always work in teams.
Yes, you CAN try, but don't be suprised if it doesn't work out like you want it.