"I really didn't think this day was going to come," she says.
Twelve months ago Smith nearly walked away from cricket altogether. At the age of 23, it's clear she thought her international hopes were behind her; she was also finding it increasingly difficult to juggle her training as an England Academy player with full-time employment.
"I'd finished university, I was coaching for Leicestershire and I didn't really have much else apart from cricket," she says. "It all got a bit too much for me and I wasn't enjoying it. I thought 'I need to make a change'. I took a step back from training for a bit."
"The ECB were really good. I spoke to Robbo [coach Mark Robinson] about what we were trying to work towards and what he wanted from me.
"I'd planned to go to Australia this winter to play out there, I thought I'd try something new, but after this year's Super League he said, 'you're on the radar. Either stay here and try and get a spot and train with us, or go to Australia'. That was the day after I got the visa as well! I decided to stay and try and get that spot, and thankfully it's paid off."
Even so, her selection in this tournament was not a certainty, by any stretch of the imagination. So much so that her parents - who were in St Lucia on Monday to see her presented with her England cap - booked to watch the England men's team play in Sri Lanka. "When I told them I'd been selected they were a bit like, 'oh! Better cancel that holiday then!'," Smith laughs.
Now here she is in the Caribbean, relishing her new role as an international cricketer. On Monday against Bangladesh she finished with figures of 1 for 17 across four overs, helping England to a seven-wicket victory. The likelihood is that she will be called on frequently to bowl in the Powerplay overs in the remainder of England's WT20 matches. It's a role she has performed admirably in the Kia Super League: she sits atop the list of leading English wicket-takers in KSL Powerplay overs.
"For me that's where I thrive," she says. "I want to be amongst the tense times and where the pressure's on. I'll stand up and take it, stand up and do the best for my team."
Coach Mark Robinson concurs. He describes Smith as "a versatile cricketer that offers something different. She can bowl at what I call the dirty parts of the game, in the Powerplay and the back end of the innings."
Robinson has had his eye on her as an England prospect ever since the inaugural KSL in 2016. That was yet another "sliding doors" moment for Smith, a tournament that she almost didn't play in after missing out on original selection for the Southern Vipers squad. It was only a head-on collision between two Vipers players during the first match of the tournament that led to Smith's call-up as an injury replacement.
"It was pretty devastating not to get in the team originally," she recalls. "I was working for Leicestershire at a Loughborough Lightning game, and [Vipers coach] Nick Denning rang me. He said, 'can you travel up to Lancashire because we need you in the squad?'"
"It was a pretty crazy way to get into the team. Originally it was just to be in the squad for one game, but then thankfully I did well enough and they thought, 'let's keep her on'."
It was in her second match, at the Ageas Bowl, where she suddenly burst onto everyone's radar. She took 4 for 10, with scalps including Alex Blackwell and Katherine Brunt; the match was broadcast on national radio and the commentators, informed late in the day about her selection, looked on in disbelief at this spinner who had come from nowhere. Afterwards, she remembers Robinson approaching her.
"He came over and said, 'well bowled'. And I was in shock because I didn't think he'd know who I was!" The rest, as they say, is history.
These 2 have always been with me by my side, when things go well, and when they don't. To have them here sharing this experience, means the absolute world. pic.twitter.com/a0mGJuz2IE— Linsey Smith (@LinseySmith95) November 13, 2018
Smith's route into cricket came courtesy of her dad and brother. "I started playing when I was about 10 years old," she says. "We moved to Oxfordshire and we joined a local club, Aston Rowant. I thought if my dad and my brother were going to sign up, I might as well do it as well. There wasn't much of a girls section then so I got stuck in with the boys, which is what I've always done really growing up."
Her talent was apparent from an early age: in the 2010 NatWest Under-15s Club Final, aged 14, she took a five-fer, leading Michael Vaughan to tweet: "remember the name: Linsey Smith".
Initially she was a seamer, but she changed to spin five years ago due to an injury niggle. "I'd had some issues with my shins and it got to a point where I was missing quite a lot of cricket," she says. "So I thought 'I'll give spin a go, the run-ups aren't too long!' Thankfully spin has done pretty well for me."
Whatever happens for the rest of the tournament, her selection has already brought Smith something which eluded her for a long time: some measure of financial security. Currently the domestic women's set-up in England, the month-long KSL aside, remains entirely amateur, and Smith has long juggled her cricket commitments with her work as a coach for Leicestershire. It was this overload which almost forced her out of the game prematurely.
That is set to change going forward, after Robinson days ago confirmed she would be given a "Rookie" contract to allow her to train full-time over the winter.
"I came out of the KSL this year thinking, 'right, I need to find a job away from cricket,'" she says. "For them to say, 'you can focus on what you want to do, focus on being a cricketer for England', it's such a relief. I feel very lucky and privileged."