I have two half sisters and two half brothers, myself being the eldest of all of them, and never living with 3 of them, but having spent some time with one half brother during childhood, and grew up with one half sister.
My siblings were an affront to my existence until I was about 12. I never felt much of a bond with any of them. Of course these days I get along much better with them than I ever have my parents. But it's still not some inseparable bond, just shared experience. I only know one of them "well", anyway. One of them I've never even met.
It affected my life in the way being firstborn affects any first child. The parents make all the mistakes with you, and try all their idealistic crap on you first, only to give up on the later kids and get lax with them. There was a slight issue with my brother in that he clearly spent a lot more time with my father who was divorced from my mother, and seemed to get a lot more attention than I ever did. I know for a fact a lot of the latest toys and clothes were bought for him that I never got, and money was put away for him and I was told the same thing was being done for me, only to be told at a later date my father had changed his mind and hadn't put anything away for me because I "didn't choose to spend enough time with him". Haha. Incidents of unequal treatment and lying continued to the point I remember saying in front of my brother I didn't believe a word my father said, which seemed to upset him. The difference between myself and my brother were that I think he was always assured my father cared about him, and the same goes for the other kids he had, but I was never assured of it, and I found his kids to be gullible where I was suspicious, and I seemed to be the only one aware of his emotional manipulation until fairly recently. My siblings are all like that - more trusting, family-oriented people. The family I lived in was poorer than the ones my other three siblings lived in, so there was that.
At the time, I liked the idea of being an only child. Probably because it was clear I was the unwanted product of an unwanted marriage, whereas all these other kids were desired and doted on. I was just "there". I think the only people who were happy I was around were my two grandmothers. One's probably rolling in her grave that I'm now a man and the other... well let's just say she wouldn't exactly be thrilled either.
I don't remember feeling jealousy toward my brothers. I was an individualist from the minute I could think and I didn't seem to care what other people were. It was what I thought of myself that mattered. To a certain degree the main sister and the eldest brother did seem to "look up" to me in some ways, but I don't think I had a significant effect on him. Didn't spend enough time around each other. My sister who lived with me would follow me around 24/7 and I would play pranks on her, make daft home made horror movies with her playing all the parts, make forts and treehouses, stage mock wars with our friends and we would generally fight constantly. I wanted privacy and she gave me zero amount of it except when watching TV or out with her friends. She was like a shadow following me around everywhere unless I could give her the slip and escape out on my own. Which I often did. I wasn't particularly nice to her I suppose, but that doesn't really matter in adulthood any more. I was on her side whenever my parents were acting up drunk, however much I might have told her to get lost during the day. Kind of a sad childhood really in some respects. I wanted to be left alone and I was deeply troubled as a kid, probably needed some sort of therapy but never got any and had to deal with all kinds of stupid family issues and drunken mother issues. It wasn't a childhood with much innocence in it. I thought of my sister as an annoyance and she most definitely seemed to put me on some sort of pedestal, as her only sibling and the main social influence she had in life. She wasn't a very feminine girl - it was after I left home that she started hanging around with other kids and seemed to become much more feminine. I wonder what she'd be like if I'd not left home.
I didn't compare myself to anyone as I was struggling to survive in my own head.
One thing I do remember wishing was that I had an older sibling that would have had my back. I was that older sibling though and had to become what I never had.
As kids, my siblings would pretty much enjoy what I enjoyed and take their cues from me. I would play video games with my brother at my father's house sometimes. As adults, my sister turned out to be super feminine and my brothers fairly typically masculine - she wants to be a make up artist and works with kids, the eldest brother is into cars and bikes in a big way, and last I heard my youngest brother was signing up for the military. No idea about the youngest sister. Interestingly it was me with all my issues who drifted from one career to the next, spent most of my adult life in academia etc. but who was usually regarded at the "most promising" kid of the bunch who apparently disappointed everyone. I have no idea what they expected me to turn out like, given the situation. I think they all expected some little wonder girl (my school grades were pretty good) but what they got was someone who distanced themselves from the untrustworthiness and backstabbing and literally went off into the blue and became a different person. I do blame my lack of focus and inability to relax on the trans condition, ever since childhood.
