Finnish as a major? Hienoa! And Iceland too? You are crazy =)
But I understand you now, e.g. 'pikkuinen' becomes 'pikkuisesta'. Only here the base word is 'normaali', so 'normaalinen' is a non-word. E.g. "To err is human, commonplace and normal" becomes "Erehtyminen on inhimillistä, tavallista ja normaalia." Only now that I am explaining this, I find that I've never had to think about this.
Oh, and to confuse you a bit more: "Do you like Eppu Normaali (a popular Finnish band)?" translates to "Pidätkö Eppu Normaalista?", instead of "Normaalia". Then again, "Do you listen to Eppu Normaali?" becomes "Kuunteletko Eppu Normaalia?"
"Normaalista" is not correct, the -sta/-stä ending (case: elatiivi) answers the question "from where". Finnish cases are a nightmare, but don't worry, we can still usually understand perfectly what you are saying. So don't hold back, you never know when it might be handy to know Finnish. Example: my friend is Indian and his coworker is Portuguese. Guess what was their only common language when this duo went on a work trip? Hint: it was not English.
I don't think you understand what I mean :P I meant that I put the word "normaalinen" (which I maybe invented) in partitive case. As you know, "-nen" stems become "-sta" in partitive singular.
And BTW, I know all that ^^ Finnish is one of my two majors in college, you don't need to convince me to keep on studying it ;) And I don't find the cases of find that the cases of Finnish are that bad: I struggle way more with the 4-case declension system of Icelandic, despite it being smaller ^^