Edit: See this post for an update (tl;dr it probably wasn't the bicalutamide, though I have reason to suspect it's actually kicking in as of 3/13/2023)
I don't know how long it takes for bicalutamide to start blocking T, but I took my first dose of it around 8pm and already by 11pm it seems to have had me feeling some kinda way, and now at 5:30am1 I genuinely feel better than I have in... basically as long as I can remember? Like, not in the normal gender euphoria way where I'm giddy about a specific thing (like feeling cute, having someone affirm my gender in certain ways, fantasizing about being involved in some hypothetical romantic scenario with someone who sees me as a girl in a specifically gay way, etc.) but instead in just a kind of passive way, like wearing particularly comfy clothes after wearing an itchy sweater or something. Is... is this what it's like not having weak gender dysphoria as constant background noise in your head??? I'm sure I must have felt like this at some point in my life, but I don't think even things like mood stabilizers, antidepressants, etc. have had this kind of impact2 on me. I've considered that it might just be one of those placebo things (specifically the kind where a medication feels like it's working before it's actually had time to start working3), but even if it is, I was not expecting to feel this good, and especially not this fast. 
(if you couldn't tell, I really like that meme format)
In the interest of not giving anyone false expectations of what bicalutamide can do (particularly not within mere hours of the first dose), I should probably mention that a few days before I started the bicalutamide, I also started taking lithium carbonate1 again after having not taken it for a while (it's... complicated, let's just say my old psychiatrist was bad at scheduling and communication), and when I asked my nurse if he had any thoughts on how fast bicalutamide is supposed to start blocking T, he said it was much more likely the lithium stabilizing my mood. And thinking about it further, that feeling of peace does actually match up with when I first started the lithium, I think, I'd just completely forgotten what that felt like because I'd been on it for a while and just took it for granted after a certain point.
Now, with that being said, it has been a week since I started, and I think I might be noticing actual effects from it? Like, specifically the ones my nurse originally mentioned when he prescribed it as a weakly feminizing anti-androgen.2 It's hard to know how many (if any) are just my imagination, given that some of these are things I thought would surely take at more than just a week, but of the ones I think are more plausibly actually happening, the one I really didn't expect to view positively in any capacity is the worse circulation. And yet, despite the obvious downside of my hands and legs falling asleep more easily if I sit wrong, somehow the slight cooling of my limbs actually feels really nice and comfy??? And I say this as someone who has historically had to wear a hoodie in basically any restaurant, who often doubles up hoodies during the colder parts of the year (even back when I was a teenager, much to the confusion of my teachers and fellow students), and who frequently wishes her parents would keep the thermostat just one degree higher in the Winter. I think maybe it's because it mostly feels limited to the outer layers of my body rather than cutting deep, so it feels kinda refreshing, like a cool blanket, though maybe there's also an element of gender euphoria in there as well?3 But hey, I'll take it, especially considering I was anticipating having a negative reaction to this change.