Can someone please just give me your opinions on this?

so I am homeschooled and since then I don’t have a lot of friends I really hang out with anymore. Just one but lately she’s been really distant. Anyways my brother has a whole group of idiotic people and they hang out all the time. I go sometimes but when I do they make me feel so unwelcomed. I always have meshed better with guys than girls but when I’m with my older brother they all treat me like I’m the stupid little sister. And we’re only 1.5 years apart, and most of their girlfriends are my age. My moms always saying why don’t you just go with him and socialize but when I do my younger sister always wants to come and I don’t want to do that bc she would make me feel even smaller there.
Am I being a jerk? I wish I could get my self to go with him but I’m scared even though I normally don’t care about this stuff.
tonight my brother got invited to go see his friends baby ducks he got and all the others were going and he asked me if anyone wanted to go see them but my sister said she would if I would and I didn’t end up going and I feel horrible like some grumpy shy lonely person who has no friends. I can’t even hang out with anyone. I feel terrible. I’m always at my house. I don't know what to do.
Can someone please just give me your opinions on this?
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