How to Avoid a Criminal Record from Shoplifting

My question involves criminal law for the state of: Maine

I'm an 18 year old female from Maine. Finishing high school. I made a huge mistake today.
I shoplifted from a store named Mardens today. It's a Maine store.
I shoplifted about $35.35 worth of makeup, just 5 or 4 items. I got caught. As soon as I was approached with my mother, we were taken out back and I just admitted up front. I was caught on camera. I deeply deeply regret doing what I did, it was dumb and stupid.
It's the first time I've ever stolen anything and I have no criminal record.
The guy who talked to me said that since I was just upfront and honest that will really help me out and it's clear I regretted what I did. I cannot be in Mardens or in their parking lots for a year or else I'll get into trouble again.
I have a summons on December 5th. I was just wondering if I should bother getting an attorney, should I plead guilty because it's obvious I did it and I know I'm guilty of what I did, how much the fine might be, and if I can ever get this off my record because I was just dumb and did something wrong and I don't want this ruining the rest of my life.

Consulting a local attorney would be the best idea. They are in the best position to advise what is possible.

Don't take legal advice from some "guy." They rarely know what they are talking about.

Never plead guilty unless you have legal counsel as to what the implications of doing so are. As one of the local attorneys here puts on billboards, just because you did it doesn't mean you're guilty.
If you plead guilty and are found guilty it is NEVER, EVER, coming off your record. Not even with a pardon from the governor or the president. Criminal convictions in your state are forever.
Some courts in your state provide "shoplifters alternative" diversion. You take the course and keep your nose clean and the charge goes away.

As LegalWriter above says, a local attorney will be able to advise you on what he can do for you.

Alright, thank you for your suggestion.
I assumed me doing it meant I was guilty, but I DO NOT want this on my record forever because I have never had a job and Im trying to get one and this would really not be good.
Ill definitely consult a local attorney.
What should I do if I cannot afford to hire an attorney?

Unless the court is positively going to offer you a diversion, ask for a public defender. If you're truly indigent, one should be provided.