I was 18 when I got arrested for credit card fraud. The judge dropped my felony to a misdemeanor put me on summary probation for 3 years. I expunged my record when I was 21. Will this affect my employment opportunities in the medical field? As a caregiver or CNA?

It could, easily.
Read this: http://www.nytimes.com/2006/10/17/us/17expunge.html?pagewanted=all&_r=0

Expungements have never meant totally gone, even before the electronic age. They were available to law enforcement. But now it's a tossup.

Absolutely agree with Joy - some agencies will find it and care on a background search. Others will not.

I would not spend money on education without some sort of decision that you can get a license.