I’m 14 and have been learning Japanese for about 1 and a half years. I study for around 4-7 hours a day. How long until I reach or almost reach fluency?

Right now I’m at an N4 level.

Edit: I forgot to mention that I only just started studying 4-7 hours a day a few months ago. Earlier I was not motivated and not that serious about it, so I studied about 1 hour a day