Can you remember your 12th birthday?
There was probably some cake - maybe even in the shape of a caterpillar - and, if you were lucky, friends, family and a few presents.
Whatever you did that day, the chances are it's not affected the rest of your life very much.
But for Joe Franklin, who possesses a trainer collection so exclusive he's become one of the go-to suppliers for the UK rap scene, that day is when it all began.
He saved up some birthday money and put it towards a pair of Jessie J's signature Nike Air Max 90s, trainers he says he only wanted to impress his friends.
"Later that day someone offered me double what I paid. So obviously I took it and I made double my money," he tells Radio 1 Newsbeat.
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Since then the most expensive pair of trainers he's sold went for £62,000, after he flew to LA and bought them from a collector for £45,000.
They were a pair of Back to the Future Nike Air Mags that laced themselves up - just like in the movie.
That's an eye-watering number but Joe - who's still only 17 and lives at home with his parents in north-west London - says the "higher net-worth" collectors he sells to see trainers like art.
Most of his clients live in Russia and Dubai - the type of people who might come to London and park their gold Lamborghinis outside Harrods over the summer.
But he also sells to a lot of UK-based rappers who want something that will make them stand out in a video shoot, or just look good.
Dizzee Rascal, AJ Tracey, Notes and M Huncho have all been clients.
The college dropout
Joe says on an average week he now makes anywhere between £5,000 and £20,000.
He was making half of that while still at school - so it's probably not surprising he ended up dropping out of college at 16 with just a couple of GCSEs.
"I had so many people getting in contact with me requesting to buy trainers and asking if I could source them trainers, and I couldn't do it while being in college. It was too much to deal with."
Joe, who's dyslexic, says he was never particularly academic anyway. But people at school saw he had an "eye for a deal".
"They could see I'm not this ultra-bright kid but that I know when there's money to be made."
He admits his parents thought him dropping out of college was "crazy" at first.
"But as as months went by and I carried on doing it, they realised it's a commodity, right?
"It's supply and demand at the end of the day. They didn't even look at it as trainers. They just saw it as a product that I could get hold of and make profit on."
He uses Instagram to show off some of his products, through @5upplied, and brings clients to a space he works out of in east London - by appointment only.
It is, Joe says, an exclusive service.
He gives the time he delivered a pair of Nike SB Dunk Paris trainers, worth £30,000, to a private jet at Luton private aviation airport - having been given just two hours to source them - as an example.
"If you need your trainers delivered to you on a runway, I can deliver them on a runway. It really doesn't matter," he says.
To make that happen he had to speed across the country - in a taxi, Joe is still learning to drive - negotiating with the collector he was sourcing the trainers from on the way.
After picking them up he got to the airport, and the buyer was "in the jet, sitting there with his wife and his kids, luggage and food everywhere. And he's like 'I can't believe you made it.
'I texted you two hours ago to get me some of the rarest trainers out and you've literally delivered them to me on a plane'."
Joe says it was a moment that really meant something to him.
"I was really humbled by what he said. Obviously you know your clients are satisfied with the service you're giving them but when they say it to you and they really mean it, it means a lot more."
Watch the Newsbeat documentary DIY Generation: Young Hustlers.
Joe says that's why he can't "fanboy" the artists who come through his doors.
"I'm here to deliver a service they can't get elsewhere. Even if Drake came in, I wouldn't act like a fanboy. It's just another potential client coming through - I'm just trying to deliver my service."
It all sounds very serious - but Joe's 17 and making a decent amount of money. Surely he's living a life some of us can only dream of? It's only natural to ask what he spends his money on.
"Honestly? I just reinvest it back into the business. I use my money to make more money."
And he reveals that his friends, who are mostly still at school or working, don't even ask him to get the rounds in at the weekend. "Not yet," he laughs.
Joe plans to expand out of trainers and launch a "social media music app - nothing that's been done before", but says he'll keep selling trainers until he finds something better to sell.
His tip to anyone wanting to start a business - which he caveats by reminding us he's still only 17 - is to "learn from your mistakes, always take criticism, just keep trying - and never give up".