I actually don't think age plays a huge role in the changes that happen. I mean, none of the changes are bone-related or anything that would be permanent if you went off HRT (except boobs). So, the changes are soft-tissue related and stuff. I'm 18 and have been on estrogen for 9 months and spiro for 17 months. No one has said anything about me looking different, but I have been called "ma'm" a few times, when I'm with another female we are a lot of the time called "ladies" and when I exited the men's bathroom an old man said to me "Hey, you went in the men's room!" Things like this never happened before HRT (except when I was 13 or 14 and had very long hair and was very petite.) It also really depends how you present yourself in public along with the (sort of subtle) effects of hormones! Like, if you dress in very masculine outfits and have short hair and hide your breast development and grow facial hair, people won't think too much! However, if you sort of dress more androgynous with baggy clothing, have a clean-shaven face and grow your hair out combined with the effects of hormones, people will start to notice more!