The real value of investing at a young age is not compound interest and having another 5-10 years of time with part of your money in the market. For most of us our earning potential will keep going up until at least our 40's, so the number of dollars you have later will swamp whatever you can save now.
The real value of starting at 25, 24, 23 is that you only have a little money to invest, and when you lose it, it will subjectively hurt more. If you wait until 30 you'll be gambling a larger pile of cash without those hard won lessons to keep you out of trouble. The money you invest at the beginning increases the effectiveness of the much larger pile of money you can invest 5 years in.
If you read enough personal finance articles, aimed at real humans, you will start to get a feel for the way in which finances, like dieting or time management, has a much larger psychological factor that the objective bean counters dismiss as if the math is all that matters. What matters most is you.