Everyone when they are growing up has this idea they will do something really cool with their life and that they will have a great job, or find some perfect house, or do something unusual and groundbreaking, or become famous, or marry Brad Pitt...etc. There's nothing wrong with fantasising about really unrealistic stuff happening (like some of the things on that list) as long as you keep it as your enjoyable fantasy world that you delve into occasionally and don't expect it to happen, otherwise you'll be perpetually disappointed.
Now it's up to you to decide where to set your standards. If you want to become a supermodel then it's a 99.9% chance you won't ever achieve it. However some people would feel 'special' if they become a parent, get a good job, find a great partner..etc.
Most people when they are growing up think that they are invincible and that doors will open for them that will open for nobody else...you do grow out of it when you realise that life is lived day by day..the good, the bad & the ugly. Compromises are made in life. Sometimes ending up doing OK is the best you can do. Everyone has horrible, boring & depressing periods in their life and even those that get some amazing dream come true have the same issues as everyone else.