Came out to my brother and now he's uncomfortable (me too)

Hey.
I'm dating my boyfriend of close to two years, and we're going great. I honestly cannot imagine being with anyone, either male or female, other than him. But I just recently had to come to terms with the obvious fact that I didn't just have "curious thoughts" for the same sex like straight people have, but I've had a few crushes (on straight girls, I know I suck at this) and the same heartbreaks for girls because I fantasized about living a whole domestic life with them.
Yup, had to be part gay.
In fact, my boyfriend knew bout all my prior crushes, and he said it was okay and he was glad I told him. So he wasn't too surprised when I came out. He made me feel better because he said that I was always like this, so nothing will change.
Nothing did but at the same time, I wanted something to change. I wanted to be more aware, accepting, and open of not just my own sexuality but the LGBT community. I wanted to discover a part of myself I denied.
So I decided to come out to my little brother, who's 15 and old enough to have his own opinions of the world, ya know.
He is the most "open" in my family when it comes to these matters. I have an older brother, but he's stressed with other matters and it would feel weird to talk about sex to someone who still sees me as his baby sister. I'd like to keep that just for a while longer. My mom and my dad made some homophobic comments in the past, but they could potentially get argumentative and violent depending on their mood that day. Rather not play that lottery.
So I thought my little brother would be a bit accepting of the bunch, even say something like "i knew it".
Last week, we were just looking at memes and I said out loud, "hey bro, I'm bi".
"No, you're not."
"How would you know?" His tone kinda changed.
"Oh so you're telling me that you liked girls before?"
"yeah." From there we just joked at the stereotypes we see in our town, before he spontaniously stayed silent and went on his phone. I just took this is a qeue to move on.
A couple days ago I made a gayish joke,
[Lemme know what you guys think: "You don't go gay, lesbian, or bisexual to hell. The saying is, 'go straight to hell'. Wake up America."]
He just responds with a rant along the lines of why am I suddenly making so many gay jokes, and just because I'm bisexual it shouldn't change anything. I was kinda taken back, I hadn't even touched the subject before then. I asked if he was uncomfortable, he said that he doesn't care and I should just go about like normal.
I called him out because he was obviously ticked by something, maybe because he was thinking about it all the time. We made obscene jokes before, all throughout growing up, and I definately made comments on women's bodies before, but it didn't bother him then. I make jokes because it's how I come to terms with things, even trauma. He just told me to not bring it up again, because he doesn't care.
From then on, he made some jokes about it, but then quickly skirts away from the topic. I don't want to bring it up again. That day he reacted like that, I felt so anxious and dirty. I couldn't believe I just told someone I'm related to such intimate details of my sexual preferences. When I see it like this, it feels extremely gross.

I was wondering if anyone else felt this way, and how they saw past that, or came to terms with that.

 

Wow! That is such a change of heart in your little brother, I'm so happy it worked out for the best Your reply means a lot, thank you for giving me some hope.

Yeahh now that I read it over I get what you're saying. But oh well, next time, folks!

 

Oof exactly, lol. We were raised to be pretty "closeted" when it comes to sexual thoughts and emotions in general. Me and my brothers try to break out of that by making raunchy jokes between each other. I guess that's why I was a bit taken back, because I thought he was more progressive but I also forgot our upbringing.
We're on ok terms, he's reaching out to me more for stuff he sees on the news or listening to music. I'm glad its not flat awkward. Thank you for your reply, it really gives me hope that it's just temporary.

Girlll you know I won't I've been like this my whole life, and feeling shame for longer. Why start again now?