I am confused about my height?

i don’t know my height cause sometimes i am 5’8 even but i think it is due to posture and when i wake up i am 5’9 even and throughout the day i go down to 5’8.5 i am not embarrassed of my height it is not bad but i would like to maybe grow to 5’10 do you all have any advice on how to maybe grow taller i am 17 i read puberty doesn’t end until around 21 for men so growth is still possible but i have had facial hair and chest hair since i was 13 is it still possible for me too grow any more and also why does my height fluctuate any help is appreciated

I am confused about my height?
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