My first day of school didn't come until 2nd grade.
I'd been homeschooled up until that point because of the poor schools where I'd come from but they were really good where we moved. I stayed homeschooled for a while after moving, but a little after the school year started my mom wanted to work so it was decided I'd start school after the winter break so I would blend in better with the lessons.
My mom drove me to school that day. I didn't come in on time, we waited until class had started so the teacher could introduce me. I was always the shy kid that hid behind my mom around strangers so being introduced wasn't exactly how I would've had things done; I didn't really have much say in it.
I listened to the teacher get all the kids to sit on the rug on the floor so she could tell them there was a new student coming; that was my cue to walk in. She told them my name and all the kids chanted hello. It was one of the few times I felt like everyone was staring at me and they actually were. I don't think they cared who I was at that point, they were just glad to have a new student to break up the monotony; I was like a new pet. I stood there, waved weakly and wished I could retreat somehow. Lucky for me, teacher kept my time in the spotlight brief and allowed me to sit down with the rest of them.
I tried to blend in as best I could (a hopeless effort) and sat in the back. Apparantly I had already made a mistake, I had to sit "Indian style" rather than on my knees. I wasn't really worried about joint health at that age but complied anyways.
I didn't say anything to any of my peers for the rest of the day, and probably for a few days afterward. I know now that wasn't the best action, but at the time it was all I could do not to run as far from that classroom as possible. Learning how to conduct myself socially was an overwhelming lesson, but the actual "school-work" was incredibly easy; I found I could already read and write better than all but one or two other students.
When the bell rang for the end of the day they started announcing buses. I panicked when I realised I didn't know what bus I rode. Teacher was nice and found me someone who lived in my neighborhood who'd show me the bus and sit with me (she later became my best friend). I was pretty excited to ride the bus actually, I'd never ridden in any large vehicle other than a moving truck once or twice. I kept asking when the bus would start moving every couple minutes, and was ecstatic that I didn't have to wear a seatbelt.
When I got home I was ready for a long break from this whole "school" thing...too bad it was just a Tuesday.