Years ago, when I was a kid, I wanted to be an orca trainer at SeaWorld. It became a dream instead, since there are hundreds of people applying for a spot that opens once a generation.
So I switched gears. I volunteered at a local zoo while I worked on my biology degree, and before I finished it, I was hired as a zookeeper. And I loved it.
For about a year. Then I realized if I stayed, and kept with the schooling, I would be hugely in debt, and still be working for under 10 bucks an hour. Yes. Even the highest paid keeper was under 15 an hour, and she worked with and helped raise baby tigers.
It became a matter of, sadly, logic and practicality: was I prepared to work for this much for years, trying to finish my degree, and hope for a raise after? Was I prepared to go onto social services and welfare to afford basic food? There was a time when my hours were cut, and my boss told me that I would never starve, as he would look the other way if I decided to raid the food prep area and take home a few dozen eggs and fruits for myself.
I ended up with a retail job. And it was never my dream job, but amazingly it helped me pay the bills and afford some nice fish. Had I stayed at the zoo I probably would have ended up hating fishkeeping, if only due to the fact I couldn't even afford nice feeder fish.
Following your dreams is a good idea, but not everyone gets to be an astronaut when they grow up. Plan accordingly and be prepared with a backup plan. Sometimes a dream job exists only in dreams.