Living Separate

Have you ever been told you have 'half' siblings? If not, basically its like 'step' but from your fathers side therefor making them your half siblings.

I have 2 half siblings that are 20 years older than me, roughly. We've never really gotten along because of the age differences and maturity levels, but because of that it has made being the 'little' sister role, very complicated. Also being in separate generations made it difficult. I've always been MY mother's child, not so much my fathers. Maybe its because we have never seen eye to eye or maybe its because he raises children differently than my mom has. I'm not sure, but what I am sure of is that age difference plays a big role in bonding. 

I've always dreamed of having a sister and finding out I had a big one was a dream come true, until she moved. My sister had gotten married and moved away to the land of California, long distance has never worked well with me, but she called constantly. Being my dads child while he was younger, and probably easier to handle, must have been nice. Now a days its rather difficult. Hes constantly repeating questions hes already asked and pushing himself farther than a man, his age, should. My sister doesn't/didn't like the idea of me still living with my father at age 20 but shoot, I'm helping him not keel over and die.
My brother has always been hard on me growing up, he seen discipline a lot more stricter in my eyes. My dad was a hard father to probably grow up and be a trouble maker with, he was very strict on his rules and ways. 'His way or the highway' and I think my brother took that highway but came back to his senses. Though my brother has chose to raise his kids the same way, with different generations its harder to get that point across.
Vacations at my brothers home, down south, was always fun and games when my parents were there. His grumpiness and attention wasn't on us kids, but more my father. Until trouble occurs, then its straight with the belt. For all 3 of us. The woman he married, Tina, was my favorite. She was relaxed and easy going, always trying to help us find things to do. My brother done screwed that up. How can you just up and leave a woman you loved and had kids with after 20+ years, for a, and I use the term loosely, ghetto man stealer. Or what we call 'Horse Head'.
My sibling and mines downfall occurred shortly after I, personally, called them and told them I was expecting with my still current boyfriend Austin. Neither of them were pleased, but not shocked and they, rudely, expected it sooner. My sister started talking down on Austin because we both were currently unemployed at the time. My brother didn't even want to speak to me and didn't until 2 months AFTER my twins were born. To this day, I'm constantly ridiculed by them or judged because I'm not married and STILL living with my folks. Working with 3 children is hard, especially with one of us working and expenses being high.
So lemme ask all of you something, do you know what its like to have 'half' siblings over 20 years older than you? If so, please help me with some advice. I, shockingly, still love my siblings even if sometimes their poor decisions are worse than ones I've made.