The best way to explain this is to show how powerful time can be when you put money in a pension.
Let's say you save £50 per month from age 20 and you retire at age 68. The government gives you your tax back on that £50. Let's say it then grows at about 7% per year.
By age 68, you could end up with more than £282,000
Your friend saves £100 a month from age 44. She gets tax back too and it grows at the same amount.
By age 68, her money is likely worth about £89,000. Even though she's paid the same amount as you over time. So she'll be a lot poorer in retirement.
That's the power you get with growing your money in a pension and a little bit of time.