My question involves criminal law for the state of: California

PLEASE HELP.

i was just in Lucky's today and i was charged with petty theft. I have this weird thing where all the things i pay with cash i put aside and those with food stamps on another side. i didn't bring my clear bag and placed my vitamins in my "purse." I really did intend to pay for them. when i got to the front i went to the "pay by yourself" counters. i was having a lot of trouble with the machines and a lady came to help me, it was really embarassing because i couldn't scan anything correctly and my stuff kept falling down. So basically my purse was still on my cart and i forgot about the vitamins inside. then my card wouldn't work so i was DOUBLE embarassed. she had to do scan it herself and i was distracted by my card not passing. i began to walk out of the store and was checking my reciept for how much balance i had on my food stamps card when they stopped me. i told them everything, but even i knew how bad i sounded. I told the guy to put what i had said on the report but he didn't. the four vitamin bottles and bandaids came out to be 95 dollars.

Basically, i just turned eighteen. i've never had anything on my record from before and i wanted to know what i should do at court? should i even try to plead not guilty? can they send me to jail for this? how long will this be on my record? can this be shown to colleges or scholarship programs? AND finally what is usually the punishment for this? is there anything i can do to mediate the punishment? i have court in one month and i'm scared shitless because i don't want my parents to find out or for it to go on my record. I feel so stupid right now. Final question do i need a public defender or is it like small claims court? The merchandise was around 95 dollars.