To my advantage

I was the nerd of the family and copped crap thru my schooling and also at home. My parents died in 2020, and it was then only me and my younger sister. I'd started my chosen career; my sister was halfway thru college. Always a popular girl, her college fees were covered by her inheritance from our late parents with a little left over to support her till she found her first career job. She did okay not well at college too busy enjoying herself was the main problem. After college in 2023 she found the world didn't revolve around her as much as she thought. Got a job, not a great job but she soon found it was a struggle to get by as her inheritance was all gone. I still had mine untouched and doing quite well careerwise. My sister's world crashed when her job ended the company closing down (bankrupt). She soon realized she was in major financial trouble, credit debt and car payments and rent with no money coming in. So, she turned to me for help. I of course took her in and sorted out her debts, paying off both the debt and car loan. She had promised to repay me as soon as she got a job, of course it wasn't easy to get another job at the time. Even selling herself on the street would have major competition, a remark she made to me one evening. I myself had used escorts for sex all my sex life till then. Being a smartass, I asked how much she would charge. To total my surprise, she responded with a hundred for a quickie and five hundred all night. So, I asked was that her brother's rate or full rate. Hoping to shock her, she wasn't shocked just replied saying it was full rate and added a third off just for my brother. I was shocked but recovered enough to say all night tonight than. She was quiet thought it over and said OKAY only pay me half and the other half off what I owe you. I got up and started to undress thinking she was playing along. She was but then she decided why the hell not, so we spent the night together. Every night from then on as well, several weeks later. We were sleeping together whether or not we were fucking, I then got a promotion, and it meant a transfer. She decided we should stay together, and we moved interstate. At our new home an old neighbor asked my sister how long we'd been married. She said twelve months as her response, told me on my getting home and she said we might as well be married. We are together all the time and fuck regularly and she then straight out asked me to get her pregnant. I thought she was just joking around, so I said OKAY I get you pregnant. She stopped all precautions from then on and is now pregnant all tests show a healthy baby girl due in July. I was at first shocked by her really wanting to have my child. But have also realized it was to my advantage, as I'd never actually dated a woman in my life. We also made it official; she now wears our late mother's wedding rings.