Sophie said she spent most of her 30s living a "really full, fun, happy life", but fears about never becoming a parent set in as she edged towards 40.
"You realise your clock's ticking and it hasn’t happened as you’d imagined it might," she said.
She decided to try for a child on her own, initially through an IUI, but miscarried.
She then froze her eggs and decided to go through IVF alone. When she had a successful frozen embryo transfer in 2021, she was dating a same-sex partner who is Martha's legal parent.
But Sophie, who spent about £30,000 on the entire process, considers herself "a solo parent".
During her pregnancy, and the early stages of motherhood, Sophie, who is in the RAF, said she didn't "ever really have a panic and certainly not any regrets".
Some scrutinised her decision, including a consultant who told her: "You're bringing a child into the world who is only going to have one parent. What if that parent dies?"
"I respected his view entirely but I know now that Martha is two turning three that we have the most special bond. She’s got a very stable life," said Sophie.
While she has already told Martha how she was conceived, Sophie said she would continue to be "open about everything" with her as her understanding deepens.
But she added that the single parenthood she planned had come with difficulties.
"You’re making all the decisions yourself, you’re doing all the worrying yourself, you don’t have someone to bounce ideas around with but …you realise how strong you are when the baby’s sick and you haven’t had any sleep," she said.