Birthday Present

I was quite lucky career wise when I left school at 15, I trained to become a plumber and after being trained I was on very good money. So, by the time I was 26 (2021) I'd my own home, but I still owed the bank a bit. Our mother had passed away in 2008 and our father in 2020, he believed to idiots and paid the price by refusing to wear a mask. He had lung problems from smoking all his life and Covid was the last straw. That left my older sister and me, she had married when pregnant and had a daughter. Her husband abandoned them in 2022 and so she needed my help. I'd dated but didn't do very well, got lucky very rarely and so I concentrated on getting my own home instead of renting. My house isn't flash but is fit for purpose. My sister and niece moved in with me after being abandoned by her husband. My sister is 22 months older than I am, but we get on quite well always have. She ran the house, and I support them, and I make extra working on my days off doing plumbing outside of my employment. Anyway, we were doing fairly well financially, I pay extra off my loan every chance I get. My sister started selling perfume soap on the internet and makes herself spending money. Not enough to support herself and her daughter but allows me to pay a little more my loan. My last birthday caught her short of cash and she had wanted to give a good present for all my help to them. It wasn't a concern of mine, as I don't really think about birthdays. But I do in the case of my sister and niece. So, as I'd been working very hard for some weeks, my birthday came, and I'd forgotten about it. My sister seen a men's magazine in my bedroom and there was a story of incest in the magazine. She hadn't thought of having sex with me until she had read that story. She had gotten aroused by the story and as we both weren't seeing anyone, she guessed I must be masturbating while reading the stories. I was as I wasn't dating and got a bit horny at times. So, on her next shopping trip she got condoms and was planning to give me sex on my birthday. But I'd to work a major job came up and I'd to work the whole weekend. Back to normal workhours from the following Tuesday and I was really tired after working 60 hours from the Friday thru Monday. So, on getting home I showered had dinner and when to bed sleeping. That lasted till the Friday I was recovered and decided to take my sister and niece out for a meal and a movie. After getting home my sister asked did, I have any work on the Saturday, and I said I'd none. Nothing more was said, I watched some TV while sister put her daughter bed. Then she said she was going to have a shower, I nodded towards her. She then said she wanted me to wash her back, that was a shock to me. She added it will be fun and I decided why not, and we showered together, and she played with my cock, and I played with breasts and pussy. We slept together afterwards and had sex again in the morning. In all I fucked 3 times all with condoms and I was quite willing to fuck her again anytime. Turns out she had also enjoyed the sex and as they once you start it hard to stop. So, she slept with me again the Saturday night as well and on the Sunday, she moved her things into my bedroom. We aren't very social people we keep to ourselves, but our neighbors know we're brother and sister. But then the state government decided to reroute a major road, and some properties were bought and mine was one of them. We had to relocate and found a similar house in a quieter neighborhood. My sister changed her surname and daughter's name back to her maiden name and put her wedding rings back on. As of then we told our new neighbors we were married. We act as man and wife and my sister forgot the condoms while shopping and decided we should risk it. Risk it we did, not once but every time thereafter starting in April, she tested positive last month to being pregnant. She is having the baby and will get tested to make sure it's healthy. It all started as a birthday present, best present I've ever gotten.