I think only the second is grammatically correct, but both are used in everyday language. Just remember to capitalize your I's :D

The second sentence's grammatically correct. According to my grammar book, this is one of the most often misused expression in USA. I will ask you something, then you tell me the answer. Did you graduate college? Or did you graduate FROM college?

I surfed over to the "Grammar Girl" website ( http://grammar.quickanddirtytips.com/graduated-or-graduated-from.aspx ) for the final word. My preference is to use, "After I graduated college, . . ." I view the phrase "graduated college" as an idiom, since literally it doesn't make sense. "Grammar Girl" says it used to be: "After I WAS graduated FROM college, . . ." (using passive form) Then: "After I graduated FROM college, . . ." (using active form) Now, more and more: "After I graduated college, . . ." (further simplification)