Don't worry it is normal to be. Anyone who is saying they are not nervous is lying trust me. I don't think the school will be too mean about you being late on the first day, but i suggest you do a practice run. See how long it takes to get from your house to school and check bus times etc.
You might not make a full new circle of friends on the first day. People tend to stick to who they know on the first day. But that doesn't mean you cant talk to people you don't know. If you sit next to someone in class, ask them about themselves, even ask if they werenervouss this morning or which primary school they are from. If you are in a tutoring group with older people ask abut the school, it will hlp you understand the school more and allow you to meet new people.
I would take your PE kit on the first day justin casee you have PE. Along with pens, pencils, rulers, rubbersetct. And you will get your books when you need themdon'tt panic :)
The most important thing is to be yourself, and if someonedoesn'tt like it they're not worth it. And be happy, people are more likely to approach you, and that willhelpp you make new friends.
Hope you have a great first day and good luck :)
Here's a website that might help.
http://www.teenissues.co.uk/moving-from-primary-school-secondary-school.html