As a Strictly Come Dancing fan well schooled in the slings and arrows of modern sporting celebrity, it was perhaps inevitable that Rebecca Adlington described her career as a "journey".

Confirming her retirement at the age of 23, with two Olympic golds and two bronze medals in her drawer and as the 800m freestyle world record holder, Britain's most decorated swimmer of modern times looked forward to her own next chapter but she leaves British Swimming at a crossroads.

"I hate the word retire. I'll never retire from swimming, it's something I'll always love to do. But as an elite athlete I won't be swimming competitively any more," she said, basking in the deserved plaudits of everyone from Lord Coe to Ian Thorpe for her achievements.

While an appearance on Strictly is not out of the question, there is one route she joked she was determined not to go down: "Everyone keeps saying to me, why don't you get really fat and then do a fitness DVD? That's not really my aim."

Instead she unveiled a new long-term goal every bit as ambitious as winning four Olympic medals – to ensure that every child leaves primary school able to swim 25 metres through her new Swim Stars programme.

Adlington insisted she felt no angst and not a little relief at having finally made the decision to quit competitive swimming after getting back in the pool at Christmas.

"It was a gradual thing. It was one of those things that just seemed right. I never once considered retiring after Beijing but it was something that I had to consider after London, particularly being a distance swimmer. The girl who won [the 800m freestyle] in London was 15. I'm 23. I did feel old, sad to say," said Adlington, who said she had ticked off all her post-Beijing goals.

"I wanted to go to a Commonwealths, I wanted to get a medal at a world championships. It was the perfect time to end on a high. Some want to milk it for as long as they can and others want to finish at the top. Ever since I was 12 or 13 I've wanted to finish on a high. I don't want to keep dragging it out."

Adlington was elated to win bronze in the 400m freestyle in London, starting in lane eight having narrowly crept into the final, but she was visibly upset at only coming third in the 800m. Yet she collected two thirds of Team GB's swimming medals, with her team-mates failing to convert the promise of the trials to the Games themselves.

Having gone from wide-eyed Olympic debutant to old hand she made her own contribution to the soul searching that followed, criticising British Swimming for not consulting the athletes on what went wrong. But she insisted the performance was not as calamitous as it was portrayed.

With Bill Furniss, her coach since the age of 12, installed as the new British Swimming head coach and a new performance director in Chris Spice, who formerly had the same role for rugby union, hockey and basketball, she said she hoped to stay involved: "We've got to let Chris and Bill come in and make their changes and then I'll see where I can fit in."

Furniss once called her a "Jekyll and Hyde character" as he described the contrast between her bubbly demeanour out of the pool and her fierce competitiveness in it. Even in retiring Adlington showed flashes of the steely streak that has made her Britain's's most successful swimmer of the modern era.

She said that while "Beijing was everything" and irrevocably changed her life – she came home to find her local swimming pool had been renamed in her honour, a pair of Jimmy Choos from the Mayor of Mansfield and her family under siege from the media – her gold and silver at the 2011 world championships in Shanghai were memorable for different reasons.

"In Beijing I was always seen as the underdog and afterwards it completely changed. Everything was so different, the attention was different. I noticed after 2010 I was getting older and needed more recovery. In Shanghai it felt as though I was back. That was the first time I realised I could still do this."

Adlington spoke too of the difficulties she had coping with the glare of the media spotlight after returning from Beijing and of how she could help younger athletes cope with the same transition.

"As a 19-year-old girl, it was having to deal with people wanting to take a photograph and talk to me. I didn't understand why they wanted to talk to me. I eat, sleep, swim, that's all I do," she said. "I'm not interesting at all. It was hard to deal with, it was overwhelming. But Beijing was without a doubt the best moment of my entire career."

Adlington said she was now committed to using her profile to encourage schools and local authorities to sign up to her Swim Stars programme.

"It always shocks me that swimming is not on the national curriculum, because it's such a life skill. We learn how to walk and run but we don't learn how to swim," she said. "We've got these floods and we live on an island! It's shocking to me that people can't swim. It's not about hammering the government, it's just hopefully about speaking to the right people, being more involved and learning more about it."

More pressingly, there is a party on Saturday to celebrate her achievements. And if she has gained new confidence out of the water, she also hopes that she has bequeathed her former team-mates more belief in it.

"No one ever expected a swimmer from this country to get two golds before Beijing," she said. "Hopefully the younger guys coming up can see that it is possible. I'm just a girl from Mansfield and I've done it."