She'll be taking her O-level exams next month at TMC Academy.
She is a permanent resident here and lives with her Thai mother, a 35-year-old homemaker.
The two are so close they share clothes and go clubbing together.
And in case you're wondering, no, she didn't name herself after the SingTel pay-TV service.
She explained it's customary for Thais to have a short nickname. Her mother saw the name "Mio" somewhere and liked it so much she started calling her that. Mio's given name is Pinsuda Kaewkongsri.
Since winning the Grid Girls competition, she's been receiving more attention too.
From around 40 friend requests a day on Facebook before the competition, she recently got about 420 requests in two days.
She doesn't like that strangers want to be friends with her just because of her looks.
Although her friends tell her men stare at her on the streets, she said they rarely come up to her and ask for her number.
Maybe it's because she looks intimidating, she said.
No boyfriend
Mio, who doesn't have a boyfriend, added: "I've not given my contact number to anyone who approached me in public, and I ignore all the Facebook requests.
"My mum told me I can't be this easy and to be really careful with the friends I make. When guys talk to me, I just act dumb, apologise and walk away...
"People think I'm cold and unfriendly, but I don't care what guys think of me. It's the way I protect myself."
She becomes friends with men only when she's certain they are not interested in her romantically and won't "cross the line".
Mio also told us she never thought she would beat 500 other girls to win the competition, adding she didn't feel confident standing next to the other contestants who were thinner and taller.
It was the first time she took part in the annual competition. The finals was held at Tampines Mall, and Mio didn't even invite her mother and friends to the event last Saturday because she didn't want them to make their way to the location for nothing.
"I don't think I'm pretty, though I have a unique look," she said.
"I thought the furthest I could go is second or third placing, so I was very upset when those were announced. I thought I didn't have a chance already.
"When the host announced (my number), I 'stoned out' and thought to myself, 'Who was that?'"
She won $10,000 and the honour of carrying the Singapore flag and flagstaff at Sunday's 2011 Formula 1 SingTel Singapore Grand Prix, but the responsibility and stress is getting to her.
Even though the flagstaff weighs less than 5kg, it feels four times heavier, she said.
"It's so long and I have to walk straight in heels. Since our first flag lesson a month ago, I've been doing push-ups every day to train my arm muscles."
She's also keeping her fingers crossed she'll meet her favourite F1 driver Lewis Hamilton this weekend.
But she admitted she'd likely be too starstruck for words if she actually meets the McLaren driver.
Still, she'd be satisfied if she gets just one photo taken with Hamilton.
She said: "But if I'm composed enough, I would tell him he's doing a very good job and to always remember he has a lot of supporters."
Why no words of adoration, we asked?
"If I go crazy on him immediately, he'll just walk away. No, I have to talk to him a bit and get him to trust me more first," she replied with a laugh.
But the celebs Mio really wants to meet are her idols from US rock band Linkin Park, who will perform here on Sunday night as part of the F1 entertainment line-up.
Chances are slim though, she said, as there are no plans for her to go to the same parties as the performers.
But for now, Mio is focusing on her immediate task at hand.
She said: "When I hold the national flag, I represent Singapore, the Grid Girls and F1...I don't want people to look down on us."
