The past progressive indicates a limited duration of time and is thus a convenient way to indicate that something took place while something else was happening.

 

when i grow up. 

 

We form ourselves to a complex individual with everything we do.

We grow, get older, get more intelligent and still we make mistakes.

Then you have to build something new with everything you learned in the past.

Something which connects the past and the future.Never forget what you’re made of. Never forget what you built-on.

Some things may seem blowy, some things are in a need of repair, some things you have to change and some things you can change easily by small movements to a new thing.

The only golden thread which runs through our lives, is our past. Although the childish being older days still exists and will attend us a lifelong. Even if we get old from the outside, get wrinkles and sometimes can't even heal, we still exists out of experiences and memories.