To do the important thing

Around 3 years ago, one of my current housemate argued with me jokingly, "if you continue living like this (not being so friendly with others), you would be lonely when you are old." Bothered me ever since. Not only because he made my future sounds so bleak, but due to the way he made old people sounds incapable of doing anything to alter their situation.

That latter obviously is true. Old people are susceptible to sickness, less mobility and motivation. Their appearance also begin to become what happens to "look old." Old people also may be less sexually attractive (from a young person point of view). But one thing I never thought of is how it conversely affect the idea of being young.

Then it occurs to me. What is so special about being young? To be specific, what is this fear that people have from being old?

At various times, I tried to imagine what I would be when I get older. Tried to imagine myself being sick, and not able to move from the bed. What's so bad about that? I could be happy as long as I don't pose people trouble. I may even have one or two significant-others-will-be that can feed and take care of me. If that's the case, then what kind of regret that I would have?
So I thought, if I continue this path of life I am taking, I don't have any problem to reach the kind of ending like above. Of course, I am simply assuming the ideal situation here, getting good job, good family, friendly surrounding, etc.

But I am probably missing something. There is definitely something in common with what people don't like about being old. I am not entirely sure myself. Perhaps I am not that wise enough to get it yet.
But still, I don't want to realize such thing only when I get old myself. That would be sad. "If I can only think about such a thing after I experienced it when I'm old, then it would be too late."

Then it occurred to me...
"Late for what?"

I almost answered that immediately. "To change."
"I want to know such a thing while I have the power to change."

I baffled.

That's true. The power to change. That's one thing that we all have while we are young.
Our attractiveness, our energy, our physical capability, those are all seems to be the fuel to change things around us.
Deep inside me, I think this could be the answer.

Sometimes I look at the shelves at book store, look at names of recorded historians that made change to the world. "So these are the people that fully use their youth," I thought.

And sometimes, I look at family members that I used to play with as a child now have their own big family. "So these are the people that use this power to raise future generation," I thought.

And at one time, when I play Assassins Creed Revelation... "So there are also people that regret for not being able to do anything despite have changed the country for good". I know... being a fictional character Ezio is, his case might be less relevant. But the fact that the game developer put such wisdom into the character shows that the idea of "power to change" is firm in their mind as well.

I need to do something. Something that I can do.