Part-time: Common? Only for seniors?

Hi all. I'm considering becoming a dental assistant, and have found a program for training. I've always loved going to the dentist and think I might be suited for it!

I've heard that many dental assistants work part-time, or at least, they can if they want to.

Other fields operate very differently. I left my full-time, incredibly well paid career/dream job, for instance, because they wouldn't allow me to go beneath 30 hours. Other fields allow part-time and even celebrate it... but not at the entry level, or only if you've been an established employee for X years.

So, my question is this: will I be able to find a job at part-time hours right after graduation? Or is part-time hard to find? I'm in a city.

Thank you!