Just remember, no matter how bad it gets, it's only a couple of years. Then real life begins and it's oodles better
Never was quite sure about the "Be yourself" bit of advice. Lots of folks are still figuring the ins and outs of things and I'd hate to tell somebody to be themselves if that meant acting like a socially slowed ****.
I guess as far as gaming goes, the vast majority of kids don't care one way or another about it when you're in school. Many of them will have heard of it (you're all the same target audience after all) and a startling number will have played. It's not the hobby that causes kids to catch flak, it's the introvertedness and lack of self-confidence that often go hand in hand with escapist hobbies that will cause you the most grief.
I guess as long as you take "Be yourself" to mean "Act like you own the place", you'll do ok. Self-confidence and a postive outlook are the two things that draw people to you the most. If you have those two things you'll have a relatively good time in high school. If you nerd herd up and circle the wagons every time somebody looks at you funny, you're in for a miserable couple of years.