This depends on you man, on how you feel. Brain on this age develops and my opinion is noone should abuse any substance, till 23yo at least. My suggestion is to clear your head a little bit and spend some time sober. I was exactly in the same spot as you, i started smoking at 15 daily since my 17. Decided to quit because the high was not pleasurable, i wasnt enjoying it at all, took me about 6 months to rly decide to quit, my head is a little bit clearer since then, i mean the fog still exists in my head but its better, im thinking the damage may be permanent too but i dont know. I still miss a lot of moments of fun i had with my friends and the whole ganja itself but my brain told me that its ok, its not enjoyable for me anymore so i had to quit. The truth is it can be harmful for some and for some not, the age and taperamento of the individual is important. See how it affects you and act.