So im level 12 now but I could only kill 3 dragons so far. 2 from quests, and one from a random encounter.
The problem isnt that I cant find dragons, I have seen 3 of them flying above me so far. The problem is, I cant fight them. I shoot arrows at them but they just dont react. I see them as red dots and when I sneak I see that they are aware of me but they make no attempt to attack me and I just cant harm them. Im currently in rivervood with one circling around the place. What should I do to start the damn fight already?

Some dragons do that, I just ignore them. If dragons are going to land, they seem to do it fairly quickly. The majority of my dragons appear and land after circling a few times.

But the problem is all the dragons i see do that. Have over 10 hours of gameplay with only one encounter. What should i do to find those I can fight?

I've had this happen to me, what I do depends on the situation if I'm out in the wilderness on my own I get the hell out of there but if there is a fort nearby or a town I try and get the dragons attention, usually with a shout or two and then try and take them near the town or fort (So I'll have help). The best one I did was when there was a Giant's camp nearby, I took the dragon towards it, being careful not to get so close to the camp so the Giants turned on me, then the Giants and Dragon fight and I pick up the pieces.

But as I say if there's no encampment around to get help just leave it be and get out of there, I haven't managed to bring a dragon down on my own yet, I'm level 12 as well

Dont feel bad. Am lvl 22. I not fought one dragon yet. None have ever attacked me and I walk everywhere

Have you done the main quest yet? Like, the third mission?

I don't think so. I am looking for the dragonstone. On that quest in whiterun.