ahahah!!)) cool

Rakas päiväkirjani, suomi on (choose your favourite curse here in genitive case) vaikeaa :)

Yep, I meant "If u can learn Finnish, u can learn anything" I've met this phrase somewhere at a forum and learnt the word "jos", so I decided to put both to kind of a good use =) After that I've already evolved and learnt "pystyä", and also "juttu" so maybe in a couple of weeks I'll come up with some deeper thought! Maybe even "dear diary, Finnish is so freaking hard", how do u say that? =)

Do you mean learning (oppia) or studying (opiskella)? If you picked the wrong verb and meant learning instead the rest of the sentence is actually closer to be correct. Also "mitä tahansa" means about "what ever" which might be closer to what you were looking for in which case you can say: "Jos voit oppia suomea, voit oppia mitä tahansa." In any case your message was clear all the time, which should count the most :)