At any age, anyone can still pursue their dreams. I saw people graduating their college degrees on their 50s but of course, if we're still far from that age we have to do the necessary and the daily grind that we used to do. We have goals to achieve and daily tasks that we should meet. Don't look at the age of yourselves, look at the progress of what you're doing. Because if there is no progress, then it means that you're not doing to yourself for fulfilling that dream that you aspire to achieve. It's never too late for one's dreams and goals to accomplish.
Well, one could say that age is just a number and that someone can chase and achieve their dreams at any age, but why shouldn't one do it earlier? You stay busy doing useless things all your life, and then when you reach your late 30s, you realize that you have dreams to follow and targets to meet, you should do something about your career and life because you have already wasted almost a half of it doing nothing. This is a problem all around the world, you will often find people who are aged but have achieved nothing in their life because they were determined early on, and now they want to do something.
I'm not saying all this to discourage anyone at any age trying to achieve something, but it's always better to start earlier, because as we age, our abilities, especially physical, starts to go down and we won't be the same again. When we are young, we tend to be more energetic and can definitely put in more efforts into something we are trying to do, but when we grow old, our bones won't stay as strong as they used to be before, we can't have the same strength anymore. This is why, it's better for us to work hard when we are young, so that we can spend our time relaxing when we are older.

Define "wasted" though.
Because this whole argument is based on the idea that there's some objective life path that everyone should pursue. Which just isn't real. It's constructed.
You say people spend youth doing "useless things" but useless according to what standard? Economic productivity? That's one metric among many. For the majority of human history people didn't have "careers" in this modern-day sense. They lived and they worked and they died.
Most important work at this time isn't about raw expenditure of energy. It's about synthesis. Understanding systems. Seeing what others miss.
Optionality has a negative value, in the present time. The system rewards early commitment, and punishes exploration, so there is a selection effect, where only people with family wealth can afford to work out what they want. So we tell others "start early, don't waste time" and call it wisdom. But it's only adapting to a broken system.
The people who "achieve nothing" aren't failing because they got a late start. They're not succeeding because they never determined what they wanted versus what they were told to want.
Starting early doesn't solve that. It just means more years of doing the wrong thing.