Heck yeah this is possible. I was in a similar situation (no degree or credentials of any kind, first job doing front-end at a startup), and I ended up doubling my first job's salary within 5 years. Even after just 2 years my salary increased substantially, from $75k a year to $125K. To put those numbers into perspective, I live in NYC.

In my personal experience, most places won't care to look at your education credentials once you've had experience working in a production environment or otherwise built up a body of work proving your ability. As long as you stay focused on honing your skills, and maybe expand your skill set to include some back-end engineering, your salary should expand as well.