Ok, first thing's first. If you wish to get a serious response from the users of this forum, then I would advise that you use atleast reasonably good english, as opposed to "lyk" and "alwayz".
Ok, rant over. Yes, it is entirely possible to have a job and still get good grades, but it does depend on how hard-working you are to begin with, and how talented you are in your chosen subjects. If you are going to do the work anyway, and want a job to kill spare time, then go for it. But, if you want to work enough to have decent money, have a healthy social life, and get good grades, I would advise that you pass on the job, and mooch off your parents, at least until after all your exams are behind you.
On the other hand, it might be a good idea to have a job, just doing a shift a week, until the holidays/end of school, then start earning money properly. That's what I did.
Anywho, I'm not entierly sure how much sense this post made, but I am fairly tired, and can't be bothered to edit it. If there's good advice, then take it.