It wasn't planned

My sister 25 single had just lost her job and with no real skills, decided to join me in my new state. I'd gotten a promotion (2024), and it came with a transfer. Our father had left us 17 years ago and hadn't kept in touch, mainly because he didn't want to pay alimony or child support our mother said. In 2023 our mother died in a shooting, not the target, just wrong place wrong time. The gunman had decided just to kill people; no real reason I was told by the investigating officer I spoke with. I'm 3years older than my sister and the only one of us to go to college. I've a good career and wasn't in any relationship like my sister. So, we traveled to our new home state, arriving I'd bought a 2bed cottage, sight unseen via the internet. It was rough looking but was structurally sound, mostly needed painting, the plumbing, electrical and roof all were good. My sister started painting the inside, as there wasn't much available work she could do at the time. On the weekend we switched to painting outside, after preparing the walls first. After 3 weekends the outside was finished, my sister decided to update the bathroom herself. Watching D I Y videos online she felt she could do it all herself, no plumbing required just tiling and painting. Once she had tiled the bathroom, she decided on doing the kitchen tiles. Christmas 2024 we kept to ourselves and one cold night we cuddled together as the power was out due a traffic accident. One thing led to another and we became lovers, not planned just happened and as we'd no condoms we decided to use the pullout method. It worked the first time, but we forgot during the second time, I came before pulling out. At first, we were both a little concerned, but the more we thought about the less we worried about it. Also, we'd started sleeping together every night thereafter. My sister got pregnant in late April, so my failure to pull out wasn't the cause of her pregnancy, it was that we'd decided to go for it as they say. We act as if we're married and it is working out just fine all tests show baby boy is healthy due anytime now.