Dream On

I must confess to being a big Aerosmith fan, and this is one of their classic songs, and one of my favourites.
Read the words while you listen to the song (and sing along – it's great for your pronunciation!) The link to the song is at the bottom of the page.
​I've explained the words in italics in the glossary below.
What do you think the song is about?

Dream On - Aerosmith 
Every time when I look in the mirror
All these lines on my face getting clearer
The past is gone
It went by, like dusk to dawn
Isn't that the way
Everybody's got their dues in life to pay

I know nobody knows
Where it comes and where it goes
I know it's everybody's sin
You got to lose to know how to win

Half my life's
In books, written pages
Live and learn from fools and from sages
You know it's true, oh
All these feelings come back to you

Sing with me, sing for the years
Sing for the laughter, sing for the tears
Sing with me, just for today
Maybe tomorrow, the good Lord will take you away

Yeah, sing with me, sing for the year
Sing for the laughter, sing for the tear
Sing with me, just for today
Maybe tomorrow, the good Lord will take you away

Dream on, dream on, dream on
Dream until your dreams come true
Dream on, dream on, dream on

Dream until your dreams come true
Dream on, dream on, dream on
Dream on, dream on, dream on

Sing with me, sing for the year
Sing for the laughter, sing for the tear
Sing with me, just for today
Maybe tomorrow, the good Lord will take you away

Sing with me, sing for the year
Sing for the laughter, sing for the tear
Sing with me, just for today
Maybe tomorrow, the good Lord will take you away

Written by Steven Tyler. Thank you to A-Z Lyrics

Glossary
It went by – This is how we talk about time passing. Time goes by.
From dusk to dawn – from sunset to sunrise
Everybody's got their dues in life to pay – everyone has some kind of duty in life, to do something they don't enjoy
sin – an action that is wrong, especially in terms of religion
sages – wise people, people who have a lot of knowledge