This is a very interesting topic! As far as I'm concerned, being a Finn means you have a Finnish citizenship, which I believe you have since you were born in Finland. That's the only requirement. Things start getting complicated if the question is more oriented towards ethnicity.

Often times ethnicity is confused with ancestry. Being 100% Finnish ethnically would pretty much require you to be born in and never leaving some small town in Kajaani. But for someone born and raised in Finland, having lived abroad only a couple years, gone to Finnish schools and working in Finland you're not far from 100% Finnish ethnically.

Personally I wouldn't even consider myself 100% Finnish, despite having lived here my whole life with ancestors for many generations also being from here. The largest reason being that I belong to the Swedish speaking minority, and speaking Finnish as my third language makes it rather difficult to speak well.

So I do understand that especially due to the language barriers it can feel a bit tiresome at times, but as you're Turkish to some degree (and speak Turkish I assume?) it just gives you a broader perspective of the world and different cultures to an extent hard to achieve by someone who's 100% one ethnicity.