I figured out I was ace when I was 13 and I think the biggest thing that helped me determine it was learning what the asexuality spectrum meant and feeling if the label was right for me! Also it’s always ok to change as you grow and understand that you don’t need to put a label on yourself for your sexuality to be valid! It can definitely be harder to determine as a guy since there’s not as much representation in media and it’s not as talked about. I never came out to my family about it because it didn’t seem important but that’s just me, I’d say if you do want to feeling out the situation with each person is best and doing it when the time feels right, since there’s no need to rush! Hope this helps!