My state school highly recommends dental work experience, if you plan to take a gap year. I know there's a few other state schools that suggest it, as well. I would contact your school to find out how much they weigh that sort of experience.
I applied to dental assist positions straight out of undergrad and got multiple offers with pay starting at $10-12 per hour for no previous experience. You're more than likely to end up working for a corporate chain or large practice run by a group of dentists, where they don't mind training since they need a lot of assistants and have a higher turn-over rate. Craigslist is a good place to start looking for a position that won't require experience. And it never hurts to ask at the places you've shadowed if they're looking for additional help.
Personally, I think as long as you continue to shadow and volunteer, you can take whatever job you want. Especially if you have solid stats. I took a job as a chemist straight out of undergrad, and I don't regret it. BUT I will warn: I was rejected from my state school this cycle. There is probably multiple factors at play for why I was rejected. But I can't help but wonder if I had taken an assistant position, would my odds have been more favorable?