The actress explained that growing up in a tough neighbourhood in south-east London meant she saw many of her peers end up on the wrong path.
"I didn't do well at school. I used to bunk off lessons a lot. I wouldn't cause trouble but I had a lot of Lola's attitude," Harold told the Sunday Mirror.
"A lot of the girls had babies at my school and that was one route I could have gone down but that wasn't for me.
"I didn't grow up in a great area - it was a tough place to live at times. A local boy who lived a few streets away from me was out one night and ran into the wrong crowd. He was stabbed and died.
"That was a massive eye-opener for me, I was only 16 but it made me realise that there are dangers out there. It made me grow up a lot and I learnt how to be street wise which helped me so much with Lola.
"Luckily I had great parents and they were able to guide me, which is something Lola has never had."
Speaking of her stint on Jamie's Dream School, she added: "Jamie Oliver was a complete life changer for me. I was so lucky to have got on that programme.
"It made me believe in myself and made me realise I could achieve whatever I wanted in life. You just need a little bit of encouragement sometimes and someone that believes in you.
"But some young people like Lola don't have that support or encouragement."