he first time Sophia Stel came to London, she slept outside in the freezing cold. The Vancouver songwriter had finished a live set last autumn, then gone out until 3am with her then crush, but when they returned to their Airbnb, they found that Stel's manager had dead-bolted the door and fallen asleep. Stel plus crush looked for a hotel but ultimately had no choice but to kip on the doorstep. "We hadn't spent that much time together and I got to see how she was in a stressful situation," Stel says, smiling at the memory. "She kept her vibe up and tried to solve it – I knew I was so in love then."

A lot has changed in Stel's life in the year since. She opened her business bank account as an artist, and that crush is now her girlfriend. "It's a lot of change, but maybe because of my Sagittarius moon, I'm fine with it to an extent," she says, only half-joking, when we meet at her publicist's office in south London, the 27-year-old Stel in her uniform of vintage hoodie and Adidas trackies.

Stel started gaining attention last summer when her swaggering, lonely-dancefloor banger I'll Take It exploded on TikTok, then honed her sound – AutoTuned vocals merging with hazy electropop – over two EPs. She recorded the second, How to Win at Solitaire, in the basement of the Vancouver club where she worked, and it seemed to absorb a bittersweet afterparty energy through the walls. She soon signed with chic film production company A24's record label, and Lorde invited her to support her live.

So having ticked off so many achievements so quickly, why shouldn't she call her debut LP The Greatest Album of all Time? The title comes from an interview in which Stel joked that, like everyone else, she wanted to make the greatest album of all time. "They made it the cover of the Instagram carousel and I was like, 'I did not mean that,'" she says. "This is the type of pressure I'm trying to avoid!" So the title is mostly tongue-in-cheek but not entirely. "I think the universe rewards confidence, and sometimes as a girl, you're not allowed to be as cocky. It's nice to try and have a louder voice. It's something I'm working on in my life."

Becoming a pop star has been a lesson in overcoming imposter syndrome. This past year, Stel has balanced performing with odd jobs painting houses and bartending. "I was so broke but I had never been around so many crazy wealthy people at the same time," she says. "Sometimes I struggle with overextending myself financially because I want to feel rich … who doesn't?"

Her debut, almost all of it self-produced, tackles all of this with typically sly humour. On the skittering, bratty anthem Bitches Talk Shit, she protests: "'Cause you're a rockstar you should have a lot of money / Course I am a pop star but I'm still very up and coming," while the narcotised drawl of On My Dick reflects the whiplash experience of her meteoric year: "Scarlet told me no new friends / Cause all they want is dividends."

Unsurprisingly, Stel keeps her circle close. She lives with two of her younger brothers and her best friend in a Vancouver apartment, paying an enviable 650CA$ (£300) each. "They all come in and out of my room while I'm making music and I can tell if something's fun because they'll stick around for a while," she smiles.

For most of her life, Stel has lived with a lot of people. She grew up as one of 11 in an ultra-religious family, and describes her upbringing as "overstimulating" and "very extreme". She found organised religion "really damaging" and has long since parted ways with it. "When you're so indoctrinated growing up, you have to be conscious of what you believe in," she says. "You learn a lot about listening to yourself and your body."

Strangely, that sounds like experience that could help her navigate her new career. "It has helped in industry decisions because if I'm told that things are one way, I'm sceptical," she admits. "That's proven to be really helpful in keeping my sanity."

Stel also works as a model, despite hating being photographed. "Though I do love that it allows me to become financially stable," she says. The brutal casting process contributed to the bluster in her lyrics. "I wanted to make an album that gave me the energy to get up and go to castings where I'm sure I'm not going to be selected, and still be confident."

Modelling for it-girl brands such as Gimaguas is in stark contrast to how Stel presents herself. For the cover of Greatest, she chose a poetic image of herself aged seven cradling a dead baby goat – a dark riff on the "greatest of all time" acronym – on the family farm. "I was sleeping in the barn with my best friend every night in the weeks leading up to the birth," she says. When it came, "one of the babies was sideways and got snapped in half so the other one suffocated inside. That's the one I'm holding."

And despite early acclaim for the record, Stel doesn't put much stock in the opinion of others. "I had a park day with my brother last year where we smoked a joint and played soccer," she says. "I was so happy and it felt very similar to playing my biggest show. That's made me really conscious of what I do – I'm not going to chase a feeling if it's going to feel pretty similar to a really good day doing anything else."