Okay, so i'm one month on estrogen as of tommorow & i've been on spiro for about 5 weeks(i started a week before estrogen). So far the absolute only changes i've noticed is that my nipples are sore/itchy and seem to be differently shaped. I also have cystic fibrosis which makes it hard for me to gain weight in general(you could compare it to having a very high metabolism). my question is, does the fact that i hardly have any body fat affect estrogen changes? Such as hip growth/fat redistribution & breast growth?
Also, when should i start experiences more changes and what changes aside from what i mentioned? I'm 18 years old currently and i'm worried that i'm not going to have a very successful physical transition because i didn't start before/at puberty and because i'm so skinny...

If that's you in the avatar you have zero to worry about

Otherwise, keep in mind that it takes months and months to see progress. Hang in there!  You'll do just fine I'm sure of it.

Yeah, seriously. You look great. Skinny is good. Gives your body and the hormones a blank canvas to work with.