The benefits of compound interest (or any sort of compound growth) for the average saver or investor are usually hugely overstated.
"If you had invested £1,000 in ABC shares 30 years ago you would now have £1 million". Except that 30 years ago you didn't have a spare £1,000 knocking around to take a punt on a random company, nor did you have the remotest idea that ABC was going to be hugely successful out of the thousands of shares you could have chosen. We don't hear much about the people who bought shares in XYZ, which went bust when the CFO embezzled all the cash and buggered off to Monaco.
Compound interest on savings is even less likely to bring huge rewards in the real world. The annual return is probably taxable (the calculations often skirt over that), and even if it isn't, inflation has always triumphed over bank interest and always will.
On the other hand, compound interest on a loan or overdraft or credit card - that you are paying - can very easily mount up. Because unlike the positive form where you start with nothing and initially accumulate almost no interest, you are starting with that large chunk of debt and it just gets bigger. And of course the compounding rate isn't 2.97% APR, it's 29.7%.
Because of all that, the single most important rule of financial literacy is to spend less than you earn, every month. If in any given month you have to spend more because of a major purchase, make a plan now to spend less for the next 3 or 6 months until you catch up. Don't kick that can down the road and tell yourself you'll do it later, because you won't. Of course some people live hand to mouth due to low incomes and necessarily high outgoings, but it seems tragic to me that people with reasonable jobs and decent incomes get into financial trouble due to excessive spending on discretionary consumption (including, these days, a lot of delivery meals and £5 sloppaccinos).
Once you are spending less than you earn, you can slowly start to save. But don't kid yourself - accumulating wealth this way is slow and hard. It's not going to magically double in four years (unless you start earning and saving a lot more). About the best you can hope for, with reasonably investments (e.g., put 100-minus-your-age-% into a low-cost worldwide share tracker fund) is to protect your savings against inflation, with maybe 3% extra APR growth on top over the longer term. There is no magic bullet and everyone has to choose how much gratification to delay, and for how long.