Becoming the UK's youngest mum, she and her baby daughter Sasha sparked a media frenzy and critics warned she'd never cope. But Jenny vowed to be a good mother and not let her daughter make the same mistakes as her.
Now, 15 years on, it seems Jenny's hard work has paid off and Sasha is a model teenager. In fact, when she discovered how young her mum was when she had her, she was appalled.
"I was embarrassed when, aged 12, I found out my mum was just 12 herself when she had me - I was devastated. I don't really tell people about it," says Sasha.
iI'm a virgin and plan to stay so until I'm at least 18 - I think teenagers having sex is disgusting. It's better to wait than risk throwing your life away.
"I love Mum and she did her best by me, but discovering she had me so young - at an age when I was still playing with Barbies - shocked me. She never had a life or much money. I'd want better for me and my kids."
And Jenny, now 27, from Poole, Dorset, who's also mum to Jessica, nine, and one-month-old Lacy-Mae, agrees.
"I never had a life as a teenage mum and I'd never want Sasha to be a young mum," she says.
As soon as she had her first period aged nine, I told her it isn't big or clever to have underage sex. If she fell pregnant now, I'd probably encourage her to have an abortion. I want her to get an education and a good job. Being a young mum is hard.
Jenny fell pregnant in 1997 when she was just 11 after 'experimenting' with sex for the first time with a 13-year- old boy from her school.
The young mum, who was living with her unemployed parents and five siblings at the time, says: "I hadn't had sex education and Mum hadn't given me 'the talk.' I didn't think I could fall pregnant the first time. Sadly, Jenny, who'd dreamt of becoming a midwife, left school at 16 with grade D and E GCSEs.
"I loved Sasha to bits and never regretted having her, but I missed out on being a teenager - I was at home looking after a baby while my carefree mates were having fun with their futures in front of them," says Jenny.
Jenny fell pregnant again at 17 with a new boyfriend:
"I'd been a mum for five years and it felt like the natural thing to do. But even though my boyfriend worked, it was a struggle to get by. If we wanted a holiday or clothes, we'd have to save for ages. I thought about working, but I didn't have any qualifications and I had the kids to care for."
Incredibly, despite knowing her mum was young, Sasha didn't realise Jenny had only been 12 when she gave birth until she was 12 herself.
"I never did the maths," says Sasha. "I was at my nan's and saw a newspaper cutting about Mum - it was a huge shock and I was embarrassed. I couldn't imagine anyone having sex or giving birth at my age. I still played with Barbies and had never had a boyfriend - I didn't even fancy boys. Some of the girls at school talked about sex, but I thought it was disgusting.
"Mum had always warned me about getting pregnant. I understood then why she'd gone on about it so much. Discovering how young she'd been made me even keener to stop it happening.
iMum was silly - but I won't be.
And Sasha is determined to remain a virgin until she's 18, insisting: "I'm not interested in dating or having sex. I kissed a boy once, but I've never had a boyfriend. I tell my friends: 'Boys will wait if they really like you.'
"I do feel pressure to have sex, but thinking about what happened to Mum puts me off. I don't want to claim benefits and live in a council house. I want to get good GCSEs, go to college, own a hair and beauty salon, buy or rent a house and get married - all before I have a baby.
iI'd like to start a family at 25 and for my kids to know their dad. You should only have a baby if you can support yourself.
And Sasha's resolution has been strengthened by sharing the house with her one-month-old sister Lacy-Mae - Jenny's daughter with her new partner, mechanic Adam Dunn, 26, who she met after splitting with Jessica's dad three years ago.
"Looking after my newborn sister is tiring - sleepless nights, nappies... no thanks!" says Sasha.
Jenny is more than happy with Sasha's views, saying: "I will warn her off sex for as long as possible. Life's been hard for me. If I hadn't had a baby so young, I know I would've done well at school."
Jenny reveals she returned to education three years ago to study for qualifications in English and maths and hopes to work when Lacy-Mae is older:
"I want Sasha to get everything out of life before she starts a family. I did the best I could for her - but I want her to give her kids more."
What a tale. Sasha sounds like a very clued-up young lady!
Words Jocelyn Cook at Closer magazine.
The full feature appears in this week's Closer magazine, on sale now.