As I said before I'm in 7th grade but I dress boyish but I'm not know as ftm I'm know as a tomboy how do I transition over ?

Hon, you're going to want to see a counselor for a good period of time before you really think seriously about transitioning. Especially as you're unsure if you're a tomboy or actually a boy. Right now, you should be thinking far more about figuring yourself out, and a counselor who knows what he/she's talking about is very important.

Let me ask a big question: do your parents know you're thinking about this? It's not necessary to tell them, and maybe not even advisable depending on your situation. However, if you think they'd be open to you seeing a counselor to discuss gender identity issues, it's something you should consider.

Also, I just want you to know that just about everyone here knows what it's like to look at (in your case) all the other girls and realize you don't have anything in common with them. It's very good that you're thinking about these things now. This is the sort of thing that for me would pop up and I would just stuff it down and ignore it, and I did this for the entire time I was in middle/high school and most of college; and repressing it led to big mental health problems I'm still coping with. If you ever need to just vent, this is a good place to do it and you can always private message me. In general, I would say seeing a good counselor on a regualr basis is your first step.   

Cogusedgender12, I'm unsure from your post whether your known as a tomboy or whether you think of yourself as one. I'm interpreting it as the former. Transitioning at school will likely require your parent's support, especially if you become the target for harassment or intimidation (something that happens to 78% of trans* individuals in grades K-12). Your parents will need to be your advocate, or you will have to be extremely resourceful in locating other resources. This is not to say it can't, or even shouldn't be done, but I firmly believe transitioning is a decision that needs to be made with your eyes wide open. I transitioned in college and to this day I still have to confront bias and discriminatory comments on a weekly, if not daily basis. Are you prepared for that? Will you have support from those around you to help you cope with a world that can be incredibly stupid? If you're unsure about bringing this to your parents are there trans* or gender and sexual minority support groups in your area you could reach out to for help.

One resource I recommend to anyone talking to their family is the book "Trans Forming Families" available through amazon. http://www.amazon.com/Trans-Forming-Families-Stories-Transgendered/dp/0615123074/ref=sr_1_1?s=books&ie=UTF8qid=1335389644&sr=1-1 This resource contains stories of how the family members of trans individuals adjusted to the realization that their child, grandchild, sibling, etc. wasn't the sex/gender they expected them to be.

I will agree with Anthropos about taking your time. There is no race to transition, and it is far more important for you to become comfortable with yourself, whoever that self may be.

One resource I will offer is the book Parrotfish. While fiction, it is a good read about an ftm who transitioned in school. Perhaps reading it might help you understand potential challenges to transitioning, and possible benefits. The full information on amazon is available here http://www.amazon.com/Parrotfish-Ellen-Wittlinger/dp/1416916229.