I wasn't sure, but thought my nipples felt different two weeks after I started taking estrogen. By three weeks they were definitely protruding more. My boobs continued to grow up until about the three month mark, where they have largely stopped doing anything.
My skin got less oily very quickly after I started blockers, and I stopped getting morning erections very quickly too. Any my sex drive evaporated. I've not tested it too often, but I can still get erections on purpose, but they're uncomfortable and achy.
My skin started to get softer a couple of months after I started Estrogen and blockers, beginning on my shoulders and outer thighs. The soft areas slowly grew and after a few months pretty much all my skin is much softer.
My body hair grows slower now, and has become less thick and lighter in some places. Facial hair is unchanged.
I look in the mirror often, and there may be some slight changes in my face, but it could just be wishful thinking.
For a long time I though I had zero direct mental changes, but I'm beginning to change my mind about that. The changes have been subtle and slow, but I'm increasingly sure they're there.
Indirect mental changes I have from very early. Just growing boobs, being less hairy and having smoother, softer skin makes me happy.
I'm sure there's other things I've forgot. But I hope that helps.