Idk for sure, but people can go an entire lifetime without knowing

Quick correction:-
There is no thing such as XYY. There are only four possibilities in sex chromosomes:-
1)XX- Girl
2)XY- Boy
3)XXY- Klinefelter's syndrome- Boy with feminine characteristics/Trans boy/gay
4) XO -Turner syndrome - Girl with underdeveloped female sex characteristics/Lesbian

Yes there is:

https://en.m.wikipedia.org/wiki/XYY_syndrome

Yeah, school and wikipedia

School can very well brainwash you with stereotypes

Textbooks actually... Also, it is probably taught in higher classes. Maybe i am with half knowledge

There are some possibilities i may have 2 y chromos (short for chromosomes)

1) taller than avg *i am taller than most of, if not, all of my family*

2) weak muscle tone *i exert a lot of spinal force here, so my spine is practically unbreakable, but my arms are not real strong tho. My legs are pretty buffed*

3) autism and ADHD

Ooh

Xxy is possible, just 1 in 1000

Then theres apparently xyyy, which is extremely rare. Only 12 people have 3 y chromosomes

Thats like 1 in 750 million

But 1 in 1000 is rare, but not to extreme extents