That is quite a good score. I scored 427 and in the 87th %tile and that is quite good and will get you into almost any grad program. To give you an Idea. the 427 of mine equayes to a 146 IQ on the WAIS scale and that is close to what I actually scored (147).
You are about the 90th %tile and that equates to an IQ of approximately the same IQ as I am 146-153.
http://www.assessmentpsychology.com/iq.htm
Also an offical score of 455 gets you into Mensa. So your score is good enough for that.